Very Strong Organosuperbases Formed by Combining Imidazole and Guanidine Bases: Synthesis, Structure, and Basicity

Czech Academy of Sciences Publication Activity Database

Vazdar, Katarina; Kunetskiy, Roman Alexejevič; Saame, J.; Kaupmees, K.; Leito, I.; Jahn, Ullrich

2014-01-01

Roč. 53, č. 5 (2014), s. 1435-1438 ISSN 1433-7851 Institutional support: RVO:61388963 Keywords : guanidine * organosuperbases * synthetic methods * basicity * UV/Vis spectroscopy Subject RIV: CC - Organic Chemistry Impact factor: 11.261, year: 2014

Guanidine hydrochloride embedded polyurethanes as antimicrobial and absorptive wound dressing membranes with promising cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Sahraro, Maryam; Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir; Sorayya, Marziyeh

2016-02-01

Preparation and assessments of novel absorptive wound dressing materials with efficient antimicrobial activity as well as very good cytocompatibility were described in this work. An amine terminated poly(hexamethylene guanidine hydrochloride) was prepared and used as curing agent of different epoxy-terminated polyurethane prepolymers. The structures of prepared materials were elucidated by evaluation of their {sup 1}H NMR and FTIR spectra. The recorded tensile strength of membranes confirmed the excellent dimensional stability of the film type dressings even at fully hydrated conditions. Therefore, these dressings could protect the wound bed from external forces during the healing period. The structurally optimized dressing membranes could preserve the desired moist environment over the wounded area, as a result of their balanced equilibrium, water absorption and water vapor transmission rate. Therefore, a very good condition for stimulation of self-healing of wound bed was attained. Also, owing to the presence of guanidine hydrochloride moieties embedded into the structure of dressings, efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were detected. In vitro cytotoxicity assay of the prepared dressings revealed cytocompatibility of these materials against fibroblast cells. Therefore, they could support cell growth and proliferation at the wounded area. - Highlights: • New polyurethane wound dressings with guanidine hydrochloride based antimicrobials • Maintaining moist and warm wound environment for accelerating healing • Proper tensile strength of dressings even at fully hydrated state • Excellent biocompatibility index due to proper selection of starting materials.

Analysis of the critical step in catalytic carbodiimide transformation: proton transfer from amines, phosphines, and alkynes to guanidinates, phosphaguanidinates, and propiolamidinates with Li and Al catalysts.

Science.gov (United States)

Rowley, Christopher N; Ong, Tiow-Gan; Priem, Jessica; Richeson, Darrin S; Woo, Tom K

2008-12-15

While lithium amides supported by tetramethylethylenediamine (TMEDA) are efficient catalysts in the synthesis of substituted guanidines via the guanylation of an amine with carbodiimide, as well as the guanylation of phosphines and conversion of alkynes into propiolamidines, aluminum amides are only efficient catalysts for the guanylation of amides. Density functional theory (DFT) calculations were used to explain this difference in activity. The origin of this behavior is apparent in the critical step where a proton is transferred from the substrate to a metal guanidinate. The activation energies of these steps are modest for amines, phosphines, and alkynes when a lithium catalyst was used, but are prohibitively high for the analogous reactions with phosphines and alkynes for aluminum amide catalysts. Energy decomposition analysis (EDA) indicates that these high activations energies are due to the high energetic cost of the detachment of a chelating guanidinate nitrogen from the aluminum in the proton transfer transition state. Amines are able to adopt an ideal geometry for facile proton transfer to the aluminum guanidinate and concomitant Al-N bond formation, while phosphines and alkynes are not.

Ferrocene-based guanidine derivatives: in vitro antimicrobial, DNA binding and docking supported urease inhibition studies.

Science.gov (United States)

Gul, Rukhsana; Rauf, Muhammad Khawar; Badshah, Amin; Azam, Syed Sikander; Tahir, Muhammad Nawaz; Khan, Azim

2014-10-06

Some novel ferrocenyl guanidines 1-8 were synthesized and characterized by different spectroscopic methods, elemental analysis and single crystal X-rays diffraction techniques. The crystallographic studies revealed that the existence of the strong non-bonding interactions facilitate these molecules to interact with biological macro-molecules like DNA that described to inherit good biological activities. The DNA interaction studies carried out by cyclic voltammetry (CV) and UV-visible spectroscopy are in close agreement with the binding constants (K) (0.79-5.4) × 10(5) (CV) and (0.72-5.1) × 10(5) (UV-vis). The shift in peak potential, current and absorption maxima of the studied ferrocenyl guanidines in the presence of DNA revealed that CV coupled with UV-vis spectroscopy could provide an opportune to characterize metal-based compounds-DNA interaction mechanism, a prerequisite for the design of new anticancer agents and understanding the molecular basis of their action. The compounds 1-8 have been screened for their antibacterial, antifungal and urease inhibition potency. A concurrent in silico study has also been applied on ferrocene moiety impregnated guanidines 1-8 to identify most active compounds having for inhibiting the activity of urease (pdb id 3LA4). Most of the compounds were found as potent inhibitors of urease and the compound 1 was found to be the most active with an IC50 of 16.83 ± 0.03 μM. The docking scores are in close agreement with the in vitro obtained IC50 values of inhibitors 1-8. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Coordination chemistry of nickel(II) nitrate with superbasic guanidines studied by electrospray mass spectrometry

Czech Academy of Sciences Publication Activity Database

Glasovac, Z.; Štrukil, V.; Eckert-Maksič, M.; Schröder, Detlef; Schlangen, M.; Schwarz, H.

2010-01-01

Roč. 290, č. 1 (2010), s. 22-31 ISSN 1387-3806 R&D Projects: GA ČR GA203/08/1487 Grant - others: ERC (XE) HORIZOMS AdG226373 Institutional research plan: CEZ:AV0Z40550506 Keywords : electrospray ionization * guanidine * ion association * nickel(II) nitrate * solvation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.009, year: 2010

The insulin secretory action of novel polycyclic guanidines: discovery through open innovation phenotypic screening, and exploration of structure-activity relationships.

Science.gov (United States)

Shaghafi, Michael B; Barrett, David G; Willard, Francis S; Overman, Larry E

2014-02-15

We report the discovery of the glucose-dependent insulin secretogogue activity of a novel class of polycyclic guanidines through phenotypic screening as part of the Lilly Open Innovation Drug Discovery platform. Three compounds from the University of California, Irvine, 1-3, having the 3-arylhexahydropyrrolo[1,2-c]pyrimidin-1-amine scaffold acted as insulin secretagogues under high, but not low, glucose conditions. Exploration of the structure-activity relationship around the scaffold demonstrated the key role of the guanidine moiety, as well as the importance of two lipophilic regions, and led to the identification of 9h, which stimulated insulin secretion in isolated rat pancreatic islets in a glucose-dependent manner. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Synthesis of zirconium guanidinate complexes and the formation of zirconium carbonitride via low pressure CVD

NARCIS (Netherlands)

Potts, S.E.; Carmalt, C.J.; Blackman, C.S.; Abou-Chabine, F.; Pugh, D.; Davies, H.O.

2009-01-01

Thin films of zirconium carbonitride have been deposited on glass at 600 °C from two novel guanidinate precursors: [ZrCp'{¿2-(iPrN)2CNMe2}2Cl] (1) and [ZrCp'2{¿2-(iPrN)2CNMe2}Cl] (2) (Cp' ) monomethylcyclopentadienyl). Both compounds 1 and 2 were structurally characterized by X-ray crystallography.

Development of Antimicrobial Coatings by Atmospheric Pressure Plasma Using a Guanidine-Based Precursor

Science.gov (United States)

2013-10-29

AP- PECVD) process to develop coatings from a guanidine-derived monomer, 1,1,3,3-tetramethylguanidine ( TMG ), that impart antimicrobial behavior onto...cleaned in ethanol and dried in open air. The antimicrobial agent, 1,1,3,3- tetramethylguanidine ( TMG ) (99%, Aldrich), was used as received. TMG ...solutions used in the deposition process included 1.0, 5.0, and 10.0% (w/w) of TMG in deionized water (Milli-Q, 18 MΩ•cm) and were used to study the role

Sidewall Covalent Functionalization of Single Wall Carbon Nanotubes through C-N Bond Forming Reactions of Fluoronanotubes with Urea, Guanidine and Thiourea (Preprint)

National Research Council Canada - National Science Library

Pulikkathara, Merlyn X; Khabashesku, Valery N

2007-01-01

...) as starting materials in the reactions with either urea, thiourea, or guanidine. Through these reactions, the derivatives with terminal amide and heteroamide groups on the nanotube sidewalls have been prepared...

Cytotoxicity and gene expression profiling of polyhexamethylene guanidine hydrochloride in human alveolar A549 cells.

Science.gov (United States)

Jung, Ha-Na; Zerin, Tamanna; Podder, Biswajit; Song, Ho-Yeon; Kim, Yong-Sik

2014-06-01

In Korea, lung disease of children and pregnant women associated with humidifier disinfectant use has become a major concern. A common sterilizer is polyhexamethylene guanidine (PHMG), a member of the guanidine family of antiseptics. This study was done to elucidate the putative cytotoxic effect of PHMG and the PHMG-mediated altered gene expression in human alveolar epithelial A549 cells in vitro. Cell viability analyses revealed the potent cytotoxicity of PHMG, with cell death evident at as low as 5 μg/mL. Death was dose- and time-dependent, and was associated with formation of intracellular reactive oxygen species, and apoptosis significantly, at even 2 μg/mL concentration. The gene expression profile in A549 cells following 24 h exposure to 5 μg/mL of PHMG was investigated using DNA microarray analysis. Changes in gene expression relevant to the progression of cell death included induction of genes related to apoptosis, autophagy, fibrosis, and cell cycle. However, the expressions of genes encoding antioxidant and detoxifying enzymes were down-regulated or not affected. The altered expression of selected genes was confirmed by quantitative reverse transcription-polymerase chain reaction and Western blot analyses. The collective data suggest that PHMG confers cellular toxicity through the generation of intracellular reactive oxygen species and alteration of gene expression. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bicyclic Guanidine Catalyzed Asymmetric Tandem Isomerization Intramolecular-Diels-Alder Reaction: The First Catalytic Enantioselective Total Synthesis of (+)-alpha-Yohimbine.

Science.gov (United States)

Feng, Wei; Jiang, Danfeng; Kee, Choon-Wee; Liu, Hongjun; Tan, Choon-Hong

2016-02-04

Hydroisoquinoline derivatives were prepared in moderate to good enantioselectivities via a bicyclic guanidine-catalyzed tandem isomerization intramolecular-Diels-Alder (IMDA) reaction of alkynes. With this synthetic method, the first enantioselective synthesis of (+)-alpha-yohimbine was completed in 9 steps from the IMDA products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Implications of the use of the labelled benzyl guanidine derivatives in nuclear medicine

International Nuclear Information System (INIS)

Zhagar, I.

1994-01-01

The development and synthesis of various labelled benzyl guanidine derivatives is described. After a brief outline of the tracer characteristics and the whole body imaging with 131- I -MIBG, 'pitfalls' of the visualization of sympathochromafine tissues and the possibilities of various pharmacological impacts on scintigraphy are discussed. Special emphasis is given to dosimetric and methodological aspects of MIBG scintigraphy in children, as well as to some new diagnostic applications of labelled benzyl guanidine in cardiology and pulmology. Whole body scintigraphy with 131-I-MIBG performed in groups of patients with pheochromocytoma, paraganglioma, neuroblastoma, medullary thyroid carcinoma, carcinoid and malignant insulinoma. Tumor, myocardial and salivary gland uptake of MIBG were estimated semi quantitatively, according to the method of Nakajo. The uptake of 131-I-MIBG was calculated from the activity measured prior and after the application and images acquired and was expressed as percent of dose administered.The results obtained confirm the high sensitivity and specificity of 131- I - MIBG in the scintigraphic evaluation of pheochromocytoma and euroblastoma. In medullary thyroid carcinoma it was found less sensitive than 99m Tc(V) -DMS A scan. The clinical evolution and uptake values were very well correlated. In patients developing bone marrow infiltration, uptake in primary tumor diminished. Good response to operative therapy in pheochromocytoma patients as well as to chemotherapy with neuroblastoma, was associated with an increase of myocardial MIBG uptake. There was highly significant negative correlation between myocardial uptake of MIBG and urinary catecholamine concentrations. Results obtained in determination 131- I -MIBG uptake in some neural crest tumors lead to the conclusion that the choice of background regions of interest can significantly influence the final results of quantification. (author)

Tris (isodecyl) guanidine degradation in the MCU system

Energy Technology Data Exchange (ETDEWEB)

Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-06-01

The current solvent blend consists of four components; an extractant, the modifier, a suppressor, and the diluent. Of the four components, only the suppressor – tris(isodecyl)guanidine (TiDG) has exhibited an appreciable depletion rate during facility operations.∇ Using data derived from MCU process samples, SRNL derived a method to predict the TiDG depletion based upon time and volume of feed processed. With the current data set, the following formula can estimate the TiDG concentrations after processing: A_t = [A₀×exp(-0.000900×t)] – [5.39E-06×volume] where A_t is the TiDG concentration (mM) at time t (days), A₀ is the TiDG concentration (mM) at time = 0, and volume is the amount of salt solution processed in gallons from time 0 to time t. The ability to use this formula as a predictive tool is limited due to the number of data points obtained for this scope of work. As such, this formula should not be used to precisely predict future TiDG concentrations.

Tetramethyl guanidine (TMG catalyzed synthesis of novel a -amino phosphonates by one-pot reaction

Directory of Open Access Journals (Sweden)

S. Annar

2010-07-01

Full Text Available An efficient method has been developed for the synthesis of a -amino phosphonates (4a-j by the three component one-pot reaction of equimolar quantities of 2-amino methyl furan (1, dimethyl / diethyl phosphite (2 and various aldehydes (3a-j in dry toluene at reflux conditions via Kabachnik – Fields reaction in high yields (70-80% in the presence of tetramethyl guanidine (TMG as catalyst. The TMG can be easily recovered from the reaction mixture after completion of the reaction and can be reused. Their antimicrobial activity has also been evaluated.

Synthesis, characterization, and thermal properties of homoleptic rare-earth guanidinates: promising precursors for MOCVD and ALD of rare-earth oxide thin films.

Science.gov (United States)

Milanov, Andrian P; Fischer, Roland A; Devi, Anjana

2008-12-01

Eight novel homoleptic tris-guanidinato complexes M[(N(i)Pr)(2)CNR(2)](3) [M = Y (a), Gd (b), Dy (c) and R = Me (1), Et (2), (i)Pr (3)] have been synthesized and characterized by NMR, CHN-analysis, mass spectrometry and infrared spectroscopy. Single crystal structure analysis revealed that all the compounds are monomers with the rare-earth metal center coordinated to six nitrogen atoms of the three chelating guanidinato ligands in a distorted trigonal prism geometry. With the use of TGA/DTA and isothermal TGA analysis, the thermal characteristics of all the complexes were studied in detail to evaluate their suitability as precursors for thin film deposition by MOCVD and ALD. The (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) showed excellent thermal characteristics in terms of thermal stability and volatility. Additionally, the thermal stability of the (i)Pr-Me(2)N-guanidinates of Y and Dy (1a, c) in solution was investigated by carrying out NMR decomposition experiments and both the compounds were found to be remarkably stable. All these studies indicate that (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) have the prerequisites for MOCVD and ALD applications which were confirmed by the successful deposition of Gd(2)O(3) and Dy(2)O(3) thin films on Si(100) substrates. The MOCVD grown films of Gd(2)O(3) and Dy(2)O(3) were highly oriented in the cubic phase, while the ALD grown films were amorphous.

Porous hydrogel of wool keratin prepared by a novel method: An extraction with guanidine/2-mercaptoethanol solution followed by a dialysis

Energy Technology Data Exchange (ETDEWEB)

Ozaki, Yuki; Takagi, Yusuke; Mori, Hideki; Hara, Masayuki, E-mail: hara@b.s.osakafu-u.ac.jp

2014-09-01

In this study, we show a novel simple method to prepare a sponge-like porous keratin hydrogel through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test and the measurement of dynamic viscoelasticity. Three types of animal cells, PC12 cells, HOS cells and murine embryonic fibroblasts, well attached and grew on the surface of the porous hydrogel. - Graphical abstract: We show a novel simple method to prepare a sponge-like porous keratin hydrogel (A, B) through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure (B) and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test (C) and the measurement of dynamic viscoelasticity (D). Three types of animal cells, PC12 cells (E), HOS cells (F) and murine embryonic fibroblasts (MEFs) (G), well attached and grew on the surface of the porous hydrogel. - Highlights: • We prepared a sponge-like porous keratin hydrogel by a novel method. • We used guanidine with 2-mercaptoethanol to extract keratin from wool fiber. • Extracted keratin was recrosslinked to form a porous keratin hydrogel in dialysis. • The keratin hydrogel had a high mechanical strength. • Three types of cells attached on the keratin hydrogel proliferated well.

Porous hydrogel of wool keratin prepared by a novel method: An extraction with guanidine/2-mercaptoethanol solution followed by a dialysis

International Nuclear Information System (INIS)

Ozaki, Yuki; Takagi, Yusuke; Mori, Hideki; Hara, Masayuki

2014-01-01

In this study, we show a novel simple method to prepare a sponge-like porous keratin hydrogel through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test and the measurement of dynamic viscoelasticity. Three types of animal cells, PC12 cells, HOS cells and murine embryonic fibroblasts, well attached and grew on the surface of the porous hydrogel. - Graphical abstract: We show a novel simple method to prepare a sponge-like porous keratin hydrogel (A, B) through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure (B) and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test (C) and the measurement of dynamic viscoelasticity (D). Three types of animal cells, PC12 cells (E), HOS cells (F) and murine embryonic fibroblasts (MEFs) (G), well attached and grew on the surface of the porous hydrogel. - Highlights: • We prepared a sponge-like porous keratin hydrogel by a novel method. • We used guanidine with 2-mercaptoethanol to extract keratin from wool fiber. • Extracted keratin was recrosslinked to form a porous keratin hydrogel in dialysis. • The keratin hydrogel had a high mechanical strength. • Three types of cells attached on the keratin hydrogel proliferated well

The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes

OpenAIRE

Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

2014-01-01

The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect....

Theoretical characterization and design of highly efficient iridium (III) complexes bearing guanidinate ancillary ligand.

Science.gov (United States)

Ren, Xin-Yao; Wu, Yong; Wang, Li; Zhao, Liang; Zhang, Min; Geng, Yun; Su, Zhong-Min

2014-06-01

A density functional theory/time-depended density functional theory was used to investigate the synthesized guanidinate-based iridium(III) complex [(ppy)2Ir{(N(i)Pr)2C(NPh2)}] (1) and two designed derivatives (2 and 3) to determine the influences of different cyclometalated ligands on photophysical properties. Except the conventional discussions on geometric relaxations, absorption and emission properties, many relevant parameters, including spin-orbital coupling (SOC) matrix elements, zero-field-splitting parameters, radiative rate constants (kr) and so on were quantitatively evaluated. The results reveal that the replacement of the pyridine ring in the 2-phenylpyridine ligand with different diazole rings cannot only enlarge the frontier molecular orbital energy gaps, resulting in a blue-shift of the absorption spectra for 2 and 3, but also enhance the absorption intensity of 3 in the lower-energy region. Furthermore, it is intriguing to note that the photoluminescence quantum efficiency (ΦPL) of 3 is significantly higher than that of 1. This can be explained by its large SOC value(n=3-4) and large transition electric dipole moment (μS3), which could significantly contribute to a larger kr. Besides, compared with 1, the higher emitting energy (ET1) and smaller (2) value for 3 may lead to a smaller non-radiative decay rate. Additionally, the detailed results also indicate that compared to 1 with pyridine ring, 3 with imidazole ring performs a better hole injection ability. Therefore, the designed complex 3 can be expected as a promising candidate for highly efficient guanidinate-based phosphorescence emitter for OLEDs applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Spectroscopic determination of lysozyme conformational changes in the presence of trehalose and guanidine.

Science.gov (United States)

Barreca, Davide; Laganà, Giuseppina; Ficarra, Silvana; Gattuso, Giuseppe; Magazù, Salvatore; La Torre, Roberto; Tellone, Ester; Bellocco, Ersilia

2013-06-01

The bioprotective action of the disaccharide trehalose has been studied against the well-known denaturating agent, guanidine hydrochloride. The results indicated a direct influence of trehalose on both enzymatic activity and conformational changes of lysozyme, as shown by the decrease of the inactivation rate constant of about 1.48-fold and the loss of α-helix structure of lysozyme. In addition, ESI-MS hydrogen-deuterium (H/D) exchange experiments allowed us to correlate the structural and dynamic features of the protein in the presence of the two additives, highlighting as trehalose remarkably influenced this exchange by decreasing local protein environment changes and solvent accessibility to the amide peptide backbone, as further evidenced by circular dichroism and (1)H NMR measurements.

Induction of cytoplasmic petite in yeast by guanidine hydrochloride

International Nuclear Information System (INIS)

Villa, L.L.; Juliani, M.H.

1980-01-01

We have studied the induction of p - mutants by guanidine hydrochloride (GuHCL) in combination with other known inducers; ethidium bromide (EB), berenil and ultraviolet light. Competition was observed when cells were simultaneously treated with optimal concentrations of EB and GuHCL; on the other hand, treatment of cells with EB in the presence of non-inducing concentrations of GuHCL resulted in the stimulation of p - induction by EB. Furthermore, using a strain which upon treatment with high EB concentrations shows recovery of respiratory competence, the presence of GuHCL did not interfere either with the early phase of induction or with the recovery phase, but it did interfere in a competitive fashion with the final irreversible phase of EB induction. In the case of berenil, a synergistic effect was seen when cells were pretreated with GuHCL. A synergistic induction was also observed when cells were submitted to UV prior to GuHCL treatment. These results suggest that GuHCL, EB and berenil act via some common step in their p - induction pathways. Moreover, GuHCL may somehow be decreasing the efficiency of dark repair of ultraviolet lesions on mitochondrial DNA. (orig.)

Determination of diethyl phthalate and polyhexamethylene guanidine in surrogate alcohol from Russia.

Science.gov (United States)

Monakhova, Yulia B; Kuballa, Thomas; Leitz, Jenny; Lachenmeier, Dirk W

2011-01-01

Analytical methods based on spectroscopic techniques were developed and validated for the determination of diethyl phthalate (DEP) and polyhexamethylene guanidine (PHMG), which may occur in unrecorded alcohol. Analysis for PHMG was based on UV-VIS spectrophotometry after derivatization with Eosin Y and (1)H NMR spectroscopy of the DMSO extract. Analysis of DEP was performed with direct UV-VIS and (1)H NMR methods. Multivariate curve resolution and spectra computation methods were used to confirm the presence of PHMG and DEP in the investigated beverages. Of 22 analysed alcohol samples, two contained DEP or PHMG. (1)H NMR analysis also revealed the presence of signals of hawthorn extract in three medicinal alcohols used as surrogate alcohol. The simple and cheap UV-VIS methods can be used for rapid screening of surrogate alcohol samples for impurities, while (1)H NMR is recommended for specific confirmatory analysis if required.

Determination of Diethyl Phthalate and Polyhexamethylene Guanidine in Surrogate Alcohol from Russia

Directory of Open Access Journals (Sweden)

Yulia B. Monakhova

2011-01-01

Full Text Available Analytical methods based on spectroscopic techniques were developed and validated for the determination of diethyl phthalate (DEP and polyhexamethylene guanidine (PHMG, which may occur in unrecorded alcohol. Analysis for PHMG was based on UV-VIS spectrophotometry after derivatization with Eosin Y and 1H NMR spectroscopy of the DMSO extract. Analysis of DEP was performed with direct UV-VIS and 1H NMR methods. Multivariate curve resolution and spectra computation methods were used to confirm the presence of PHMG and DEP in the investigated beverages. Of 22 analysed alcohol samples, two contained DEP or PHMG. 1H NMR analysis also revealed the presence of signals of hawthorn extract in three medicinal alcohols used as surrogate alcohol. The simple and cheap UV-VIS methods can be used for rapid screening of surrogate alcohol samples for impurities, while 1H NMR is recommended for specific confirmatory analysis if required.

Discovery and structure-activity relationships of (2-(arylthio)benzylideneamino)guanidines as a novel series of potent apoptosis inducers.

Science.gov (United States)

Zhang, Han-Zhong; Crogan-Grundy, Candace; May, Chris; Drewe, John; Tseng, Ben; Cai, Sui Xiong

2009-04-01

1-(2-(2,5-Dimethoxyphenylthio)benzylidene)semicarbazide (2a) was discovered as a potent apoptosis inducer through our cell based HTS assay. SAR study led to the discovery of a more aqueous soluble analog (2-(2,5-dimethoxyphenylthio)-6-methoxybenzylideneamino)guanidine (5e) with EC(50) value of 60 nM in the caspase activation assay and GI(50) value of 62 nM in the growth inhibition assay in T47D cells. Compound 5e was found to be an inhibitor of tubulin polymerization and efficacious in a MX-1 breast tumor model.

Sigma receptor ligand N,N'-di-(ortho-tolyl)guanidine inhibits release of acetylcholine in the guinea pig ileum.

Science.gov (United States)

Cambell, B G; Keana, J F; Weber, E

1991-11-26

The inhibition of stimulated contractions of the guinea pig ileum longitudinal muscle/myenteric plexus preparation by sigma receptor ligands has been previously described. In this study, the stimulated release of [3H]acetylcholine from cholinergic nerve terminals in this same preparation was monitored in the presence and absence of sigma receptor ligands. N,N'-Di-(orthotolyl)guanidine (DTG) and other compounds selective for the sigma receptor inhibited stimulated [3H]acetylcholine release. These results suggest that their inhibition of stimulated contractions in this preparation was mediated by inhibition of acetylcholine release.

Blood-brain transfer and antinociception of linear and cyclic N-methyl-guanidine and thiourea-enkephalins

DEFF Research Database (Denmark)

Verbeken, Mathieu; Wynendaele, Evelien; Mauchauffee, Elodie

2015-01-01

Enkephalins are active in regulation of nociception in the body and are key in development of new synthetic peptide analogs that target centrally located opioid receptors. In this study, we investigated the in vivo blood–brain barrier (BBB) penetration behavior and antinociceptive activity of two...... cyclic enkephalin analogs with a thiourea (CycS) or a N-methyl-guanidine bridge (CycNMe), and their linear counterparts (LinS and LinNMe) in mice, as well as their in vitro metabolic stability. 125I-LinS had the highest blood–brain clearance (K1 = 3.46 μL/g min), followed by 125I-LinNMe, 125I...

Readily Available Chiral Benzimidazoles-Derived Guanidines as Organocatalysts in the Asymmetric α-Amination of 1,3-Dicarbonyl Compounds.

Science.gov (United States)

Benavent, Llorenç; Puccetti, Francesco; Baeza, Alejandro; Gómez-Martínez, Melania

2017-08-11

The synthesis and the evaluation as organocatalysts of new chiral guanidines derived from benzimidazoles in the enantioselective α-amination of 1,3-dicarbonyl compounds using di- t -butylazodicarboxylate as aminating agent is herein disclosed. The catalysts are readily synthesized through the reaction of 2-chlorobezimidazole and a chiral amine in moderate-to-good yields. Among all of them, those derived from ( R )-1-phenylethan-1-amine ( 1 ) and ( S )-1-(2-naphthyl)ethan-1-amine ( 3 ) turned out to be the most efficient for such asymmetric transformation, rendering good-to-high yields and moderate-to-good enantioselectivities for the amination products.

Determination of pyrophosphate and sulfate using polyhexamethylene guanidine hydrochloride-stabilized silver nanoparticles.

Science.gov (United States)

Terenteva, E A; Apyari, V V; Dmitrienko, S G; Garshev, A V; Volkov, P A; Zolotov, Yu A

2018-04-01

Positively charged polyhexamethylene guanidine hydrochloride-stabilized silver nanoparticles (PHMG-AgNPs) were prepared and applied as a colorimetric probe for single-step determination of pyrophosphate and sulfate. The approach is based on the nanoparticles aggregation leading to change in their absorption spectra and color of the solution. Due to both electrostatic and steric stabilization these nanoparticles show decreased sensitivity relatively to many common anions, which allows for simple and rapid direct single-step determination of pyrophosphate and sulfate. Effects of different factors (time of interaction, pH, concentrations of anions and the nanoparticles) on aggregation of PHMG-AgNPs and analytical performance of the procedure were investigated. The method allows for the determination of pyrophosphate and sulfate in the range of 0.16-2μgmL -1 and 20-80μgmL -1 with RSD of 2-5%, respectively. The analysis can be performed using either spectrophotometry or naked-eye detection. Practical application of the method was shown by the example of pyrophosphate determination in baking powder sample. Copyright © 2017 Elsevier B.V. All rights reserved.

Guanidine-based polymer brushes grafted onto silica nanoparticles as efficient artificial phosphodiesterases.

Science.gov (United States)

Savelli, Claudia; Salvio, Riccardo

2015-04-07

Polymer brushes grafted to the surface of silica nanoparticles were fabricated by atom-transfer radical polymerization (ATRP) and investigated as catalysts in the cleavage of phosphodiesters. The surfaces of silica nanoparticles were functionalized with an ATRP initiator. Surface-initiated ATRP reactions, in varying proportions, of a methacrylate moiety functionalized with a phenylguanidine moiety and an inert hydrophilic methacrylate species afforded hybrid nanoparticles that were characterized with potentiometric titrations, thermogravimetric analysis, and SEM. The activity of the hybrid nanoparticles was tested in the transesterification of the RNA model compound 2-hydroxypropyl para-nitrophenylphosphate (HPNP) and diribonucleoside monophosphates. A high catalytic efficiency and a remarkable effective molarity, thus overcoming the effective molarities previously observed for comparable systems, indicate the existence of an effective cooperation of the guanidine/guanidinium units and a high level of preorganization in the nanostructure. The investigated system also exhibits a marked and unprecedented selectivity for the diribonucleoside sequence CpA. The results presented open up the way for a novel and straightforward strategy for the preparation of supramolecular catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of polyhexamethylene guanidine phosphate on human gingival fibroblasts.

Science.gov (United States)

Vitt, Anton; Slizen, Veronica; Boström, Elisabeth A; Yucel-Lindberg, Tülay; Kats, Anna; Sugars, Rachael V; Gustafsson, Anders; Buhlin, Kåre

2017-10-01

Polyhexamethylene guanidine phosphate (PHMG-P) was compared to chlorhexidine (CHX) in order to determine potential cytotoxic and immune-modulatory effects on human gingival fibroblasts. Cytotoxic effects of PHMG-P and CHX on human gingival fibroblasts were assessed using cell viability assay at various time points and concentrations. The effects of PHMG-P and CHX on the secretion of prostaglandin (PG) E 2 , interleukin (IL)-6, IL-8 and matrix metalloproteinase (MMP)-1 by non-stimulated or IL-1β stimulated fibroblasts were evaluated by enzyme-linked immunosorbent assays. PHMG-P concentration 0.00009% led to the total loss of fibroblast viability within 24 h, whereas inhibition of fibroblast viability by CHX occurred at significantly higher concentrations of 0.0009% (p PHMG-P led to loss of fibroblast viability after 5 min, whilst cells exposed to 0.005% CHX survived 30 min of treatment (p PHMG-P or CHX at concentrations of 0.000045 or 0.0.00009% resulted in significantly decreased PGE 2 , IL-6, IL-8 and MMP-1 levels. PHMG-P or CHX alone did not affect the baseline secretion of PGE 2 , IL-6, IL-8 or MMP-1 by gingival fibroblasts. Cytotoxic effects on gingival fibroblasts were triggered by both PHMG-P and CHX at concentrations below those used in clinical practice. The tested antiseptics did not cause inflammation and reduced IL-1β-induced secretion of inflammatory mediators and collagenase by gingival fibroblasts, which suggests anti-inflammatory properties.

A preliminary safety evaluation of polyhexamethylene guanidine hydrochloride.

Science.gov (United States)

Asiedu-Gyekye, Isaac Julius; Mahmood, Seidu Abdulai; Awortwe, Charles; Nyarko, Alexander Kwadwo

2014-01-01

Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent with broad spectra of activity and also for treating pool water. This non-GLP preliminary study aims at investigating in a subchronic toxicity study possible effects at supra-optimal doses of this biocide. Both acute and subchronic toxicity studies were conducted. LD(50) for PHMGH was estimated to be 600 mg/kg (ie LC(50) 2 ml of 7.5% solution) when administered as a single dose by gavage via a stomach tube in accordance with the expected route of administration. The acute studies showed that the median lethal dose (LD(50)) of 600 mg/kg was accompanied by signs of neurotoxicity. Haematological and biochemical parameters of subchronic toxicity studies were non-significant. Subchronic doses of 0.006 mg/kg, 0.012 mg/kg and 0.036 mg/kg were administered. 20% of the animals at a dose of 0.006 mg/kg and 0.036 mg/kg showed mild degrees of hydropic changes in proximal tubules while 10% of animals at all the doses had their liver tissues showing local areas of mild pericentral hepatocytes degeneration. PHMGH did not produce any major organ defect with regard to the kidney, heart, and liver. The LD(50) was much higher than the recommended dosage by a factor of about 50,000. The recommended residual concentration is far less than the median lethal dose using rats as test subjects. These results could serve as a basis for investigating the full toxicological profile if it is to be used for the treatment of raw water to make it potable. © The Author(s) 2014.

Sampling polyhexamethylene guanidine aerosols using eosin Y-coated glass beads

International Nuclear Information System (INIS)

Choi, Sang Hyun; Park, Seon Kyung; Kang, Hyun Joong; Kwon, Jung Hwan; Lee, Kyu Hong

2015-01-01

Fatalities caused by the use of polyhexamethylene guanidine (PHMG), a general-purpose chemical germicide used as a humidifier disinfectant in Korea, have raised concerns about exposure to biocide aerosols in indoor environments. A sampler capable of accumulating PHMG from aqueous aerosols was developed as an alternative to low-volume air samplers. This sampler was prepared by placing glass beads coated with 2-(2,4,5,7-tetrabromo-6-oxido-3-oxo-3H-xanthen-9-yl)benzoate (Eosin Y) in a custom-made plastic holder. Passive sampling rates, measured in a bench-top exposure chamber at two different aqueous PHMG aerosol generation rates, were found to be independent of the experimental conditions. This suggests that the capacity of the sampler to accumulate the PHMG aerosol was sufficient for the sampling duration tested. However, the passive sampling rate was 7.6 × 10"−"6 m"3/h for the sampler area of 22 cm"2. This rate is lower than the typical human breathing rate and inadequate for quantitative instrumental analyses at low concentrations in indoor air. A 30-fold enhancement of the sampling rate was achieved by forced convection using a commercial battery-operated fan at ≥2000 rpm. With this accelerated sampling rate, the sampler could be used to monitor time-integrated concentrations of PHMG aerosols in the air

Sampling polyhexamethylene guanidine aerosols using eosin Y-coated glass beads

Energy Technology Data Exchange (ETDEWEB)

Choi, Sang Hyun; Park, Seon Kyung; Kang, Hyun Joong; Kwon, Jung Hwan [Korea University, Seoul (Korea, Republic of); Lee, Kyu Hong [Korea Institute of Toxicology, Jeongeup (Korea, Republic of)

2015-07-15

Fatalities caused by the use of polyhexamethylene guanidine (PHMG), a general-purpose chemical germicide used as a humidifier disinfectant in Korea, have raised concerns about exposure to biocide aerosols in indoor environments. A sampler capable of accumulating PHMG from aqueous aerosols was developed as an alternative to low-volume air samplers. This sampler was prepared by placing glass beads coated with 2-(2,4,5,7-tetrabromo-6-oxido-3-oxo-3H-xanthen-9-yl)benzoate (Eosin Y) in a custom-made plastic holder. Passive sampling rates, measured in a bench-top exposure chamber at two different aqueous PHMG aerosol generation rates, were found to be independent of the experimental conditions. This suggests that the capacity of the sampler to accumulate the PHMG aerosol was sufficient for the sampling duration tested. However, the passive sampling rate was 7.6 × 10{sup −6} m{sup 3}/h for the sampler area of 22 cm{sup 2}. This rate is lower than the typical human breathing rate and inadequate for quantitative instrumental analyses at low concentrations in indoor air. A 30-fold enhancement of the sampling rate was achieved by forced convection using a commercial battery-operated fan at ≥2000 rpm. With this accelerated sampling rate, the sampler could be used to monitor time-integrated concentrations of PHMG aerosols in the air.

Using guanidine-hydrochloride for fast and efficient protein digestion and single-step affinity-purification mass spectrometry

DEFF Research Database (Denmark)

Poulsen, Jon Wriedt; Madsen, Christian Toft; Young, Clifford

2013-01-01

be optimally completed within 30 min with endoprotease Lys-C. No chemical artifacts were introduced when samples were incubated in Gnd-HCl at 95 °C, making Gnd-HCl an appropriate digestion buffer for shotgun proteomics. Current methodologies for investigating protein-protein interactions (PPIs) often require......Protein digestion is an integral part of the "shotgun" proteomics approach and commonly requires overnight incubation prior to mass spectrometry analysis. Quadruplicate "shotgun" proteomic analysis of whole yeast lysate demonstrated that Guanidine-Hydrochloride (Gnd-HCl) protein digestion can....... To validate the Gnd-HCl approach, label-free PPI analysis of several GFP-tagged yeast deubiquitinating enzymes was performed. The identification of known interaction partners demonstrates the utility of the optimized Gnd-HCl protocol that is also scalable to the 96 well-plate format....

Polyhexamethylene guanidine hydrochloride shows bactericidal advantages over chlorhexidine digluconate against ESKAPE bacteria.

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Zhou, Zhongxin; Wei, Dafu; Lu, Yanhua

2015-01-01

More information regarding the bactericidal properties of polyhexamethylene guanidine hydrochloride (PHMG) against clinically important antibiotic-resistant ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens needs to be provided for its uses in infection control. The bactericidal properties of PHMG and chlorhexidine digluconate (CHG) were compared based on their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations, and time-course-killing curves against clinically important antibiotic-susceptible and antibiotic-resistant ESKAPE pathogens. Results showed that PHMG exhibited significantly higher bactericidal activities against methicillin-resistant Staphylococcus aureus, carbapenem-resistant Klebsiella pneumoniae, and ceftazidime-resistant Enterobacter spp. than CHG. A slight bactericidal advantage over CHG was obtained against vancomycin-resistant Enterococcus faecium, ciprofloxacin- and levofloxacin-resistant Acinetobacter spp., and multidrug-resistant Pseudomonas aeruginosa. In previous reports, PHMG had higher antimicrobial activity against almost all tested Gram-negative bacteria and several Gram-positive bacteria than CHG using MIC test. These studies support the further development of covalently bound PHMG in sterile-surface materials and the incorporation of PHMG in novel disinfectant formulas. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes.

Science.gov (United States)

Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

2014-11-01

The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect. PHMG derivatives introduced into PLA affected the activity of microbial hydrolases to a small extent. This means that the introduction of PHMG derivatives into PLA will not reduce its enzymatic biodegradation significantly. On the other hand, PHMG derivatives introduced into PLA strongly affected dehydrogenases activity in S. aureus than in E. coli.

A chiral analog of the bicyclic guanidine TBD: synthesis, structure and Brønsted base catalysis

Directory of Open Access Journals (Sweden)

Mariano Goldberg

2016-08-01

Full Text Available Starting from (S-β-phenylalanine, easily accessible by lipase-catalyzed kinetic resolution, a chiral triamine was assembled by a reductive amination and finally cyclized to form the title compound 10. In the crystals of the guanidinium benzoate salt the six membered rings of 10 adopt conformations close to an envelope with the phenyl substituents in pseudo-axial positions. The unprotonated guanidine 10 catalyzes Diels–Alder reactions of anthrones and maleimides (25–30% ee. It also promotes as a strong Brønsted base the retro-aldol reaction of some cycloadducts with kinetic resolution of the enantiomers. In three cases, the retro-aldol products (48–83% ee could be recrystallized to high enantiopurity (≥95% ee. The absolute configuration of several compounds is supported by anomalous X-ray diffraction and by chemical correlation.

Low-dose cadmium exposure exacerbates polyhexamethylene guanidine-induced lung fibrosis in mice.

Science.gov (United States)

Kim, Min-Seok; Kim, Sung-Hwan; Jeon, Doin; Kim, Hyeon-Young; Han, Jin-Young; Kim, Bumseok; Lee, Kyuhong

2018-01-01

Cadmium (Cd) is a toxic metal present in tobacco smoke, air, food, and water. Inhalation is an important route of Cd exposure, and lungs are one of the main target organs for metal-induced toxicity. Cd inhalation is associated with an increased risk of pulmonary diseases. The present study aimed to assess the effects of repeated exposure to low-dose Cd in a mouse model of polyhexamethylene guanidine (PHMG)-induced lung fibrosis. Mice were grouped into the following groups: vehicle control (VC), PHMG, cadmium chloride (CdCl 2 ), and PHMG + CdCl 2 . Animals in the PHMG group exhibited increased numbers of total cells and inflammatory cells in the bronchoalveolar lavage fluid (BALF) accompanied by inflammation and fibrosis in lung tissues. These parameters were exacerbated in mice in the PHMG + CdCl 2 group. In contrast, mice in the CdCl 2 group alone displayed only minimal inflammation in pulmonary tissue. Expression of inflammatory cytokines and fibrogenic mediators was significantly elevated in lungs of mice in the PHMG group compared with that VC. Further, expression of these cytokines and mediators was enhanced in pulmonary tissue in mice administered PHMG + CdCl 2 . Data demonstrate that repeated exposure to low-dose Cd may enhance the development of PHMG-induced pulmonary fibrosis.

Oleanolic acid acetate attenuates polyhexamethylene guanidine phosphate-induced pulmonary inflammation and fibrosis in mice.

Science.gov (United States)

Kim, Min-Seok; Han, Jin-Young; Kim, Sung-Hwan; Jeon, Doin; Kim, Hyeon-Young; Lee, Seung Woong; Rho, Mun-Chual; Lee, Kyuhong

2018-06-01

Oleanolic acid acetate (OAA), triterpenoid compound isolated from Vigna angularis (azuki bean), has been revealed anti-inflammatory in several studies. We investigated the effects of OAA against polyhexamethylene guanidine phosphate (PHMG-P)-induced pulmonary inflammation and fibrosis in mice. OAA treatment effectively alleviated PHMG-P-induced lung injury, including the number of total and differential cell in BAL fluid, histopathological lesions and hydroxyproline content in a dose dependent manner. Moreover, OAA treatment significantly decreased the elevations of IL-1β, IL-6, TNF-α, TGF-β1, and fibronectin, and the activation of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in the lungs of PHMG-P-treated mice. Cytokines are known to be key modulators in the inflammatory responses that drive progression of fibrosis in injured tissues. The activation of NLRP3 inflammasome has been reported to be involved in induction of inflammatory cytokines. These results indicate that OAA may mitigate the inflammatory response and development of pulmonary fibrosis in the lungs of mice treated with PHMG-P. Copyright © 2018. Published by Elsevier B.V.

Highly Active N,O Zinc Guanidine Catalysts for the Ring-Opening Polymerization of Lactide.

Science.gov (United States)

Schäfer, Pascal M; Fuchs, Martin; Ohligschläger, Andreas; Rittinghaus, Ruth; McKeown, Paul; Akin, Enver; Schmidt, Maximilian; Hoffmann, Alexander; Liauw, Marcel A; Jones, Matthew D; Herres-Pawlis, Sonja

2017-09-22

New zinc guanidine complexes with N,O donor functionalities were prepared, characterized by X-Ray crystallography, and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl 2 (DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (M w =69 100, polydispersity=1.4). The complexes were tested with different monomer-to-initiator ratios to determine the rate constant k p . Furthermore, a polymerization with the most active complex C1 was monitored by in situ Raman spectroscopy. Overall, conversion of up to 90 % can be obtained. End-group analysis was performed to clarify the mechanism. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solute's perspective on how trimethylamine oxide, urea, and guanidine hydrochloride affect water's hydrogen bonding ability.

Science.gov (United States)

Pazos, Ileana M; Gai, Feng

2012-10-18

While the thermodynamic effects of trimethylamine oxide (TMAO), urea, and guanidine hydrochloride (GdnHCl) on protein stability are well understood, the underlying mechanisms of action are less well characterized and, in some cases, even under debate. Herein, we employ the stretching vibration of two infrared (IR) reporters, i.e., nitrile (C≡N) and carbonyl (C═O), to directly probe how these cosolvents mediate the ability of water to form hydrogen bonds with the solute of interest, e.g., a peptide. Our results show that these three agents, despite having different effects on protein stability, all act to decrease the strength of the hydrogen bonds formed between water and the infrared probe. While the behavior of TMAO appears to be consistent with its protein-protecting ability, those of urea and GdnHCl are inconsistent with their role as protein denaturants. The latter is of particular interest as it provides strong evidence indicating that although urea and GdnHCl can perturb the hydrogen-bonding property of water their protein-denaturing ability does not arise from a simple indirect mechanism.

Integration of Bromine and Cyanogen Bromide Generators for the Continuous-Flow Synthesis of Cyclic Guanidines.

Science.gov (United States)

Glotz, Gabriel; Lebl, René; Dallinger, Doris; Kappe, C Oliver

2017-10-23

A continuous-flow process for the in situ on-demand generation of cyanogen bromide (BrCN) from bromine and potassium cyanide that makes use of membrane-separation technology is described. In order to circumvent the handling, storage, and transportation of elemental bromine, a continuous bromine generator using bromate-bromide synproportionation can optionally be attached upstream. Monitoring and quantification of BrCN generation was enabled through the implementation of in-line FTIR technology. With the Br 2 and BrCN generators connected in series, 0.2 mmol BrCN per minute was produced, which corresponds to a 0.8 m solution of BrCN in dichloromethane. The modular Br 2 /BrCN generator was employed for the synthesis of a diverse set of biologically relevant five- and six-membered cyclic amidines and guanidines. The set-up can either be operated in a fully integrated continuous format or, where reactive crystallization is beneficial, in semi-batch mode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Damage of Escherichia coli membrane by bactericidal agent polyhexamethylene guanidine hydrochloride: micrographic evidences.

Science.gov (United States)

Zhou, Z X; Wei, D F; Guan, Y; Zheng, A N; Zhong, J J

2010-03-01

The purpose of this study was to provide micrographic evidences for the damaged membrane structure and intracellular structure change of Escherichia coli strain 8099, induced by polyhexamethylene guanidine hydrochloride (PHMG). The bactericidal effect of PHMG on E. coli was investigated based on beta-galactosidase activity assay, fluorescein-5-isothiocyanate confocal laser scanning microscopy, field emission scanning electron microscopy and transmission electron microscopy. The results revealed that a low dose (13 microg ml(-1)) of PHMG slightly damaged the outer membrane structure of the treated bacteria and increased the permeability of the cytoplasmic membrane, while no significant damage was observed to the morphological structure of the cells. A high dose (23 microg ml(-1)) of PHMG collapsed the outer membrane structure, led to the formation of a local membrane pore across the membrane and badly damaged the internal structure of the cells. Subsequently, intracellular components were leaked followed by cell inactivation. Dose-dependent membrane disruption was the main bactericidal mechanism of PHMG. The formation of the local membrane pores was probable after exposure to a high dose (23 microg ml(-1)) of PHMG. Micrographic evidences were provided about the damaged membrane structure and intracellular structure change of E. coli. The presented information helps understand the bactericidal mechanism of PHMG by membrane damage.

Synthesis and characterization of azo-guanidine based alcoholic media naked eye DNA sensor

Science.gov (United States)

Hashmat, Uzma; Yousaf, Muhammad; Lal, Bhajan; Ullah, Shafiq; Holder, Alvin A.; Badshah, Amin

2016-01-01

DNA sensing always has an open meadow of curiosity for biotechnologists and other researchers. Recently, in this field, we have introduced an emerging class of molecules containing azo and guanidine functionalities. In this study, we have synthesized three new compounds (UA1, UA6 and UA7) for potential application in DNA sensing in alcoholic medium. The synthesized materials were characterized by elemental analysis, FTIR, UV-visible, 1H NMR and 13C NMR spectroscopies. Their DNA sensing potential were investigated by UV-visible spectroscopy. The insight of interaction with DNA was further investigated by electrochemical (cyclic voltammetry) and hydrodynamic (viscosity) studies. The results showed that compounds have moderate DNA binding properties, with the binding constants range being 7.2 × 103, 2.4 × 103 and 0.2 × 103 M−1, for UA1, UA6 and UA7, respectively. Upon binding with DNA, there was a change in colour (a blue shift in the λmax value) which was observable with a naked eye. These results indicated the potential of synthesized compounds as DNA sensors with detection limit 1.8, 5.8 and 4.0 ng µl−1 for UA1, UA6 and UA7, respectively. PMID:28018613

Moessbauer spectroscopic evidence on the heme binding to the proximal histidine in unfolded carbonmonoxy myoglobin by guanidine hydrochloride

Energy Technology Data Exchange (ETDEWEB)

Harami, Taikan, E-mail: harami.taikan@jaea.go.jp [Japan Atomic Energy Agency (Japan); Kitao, Shinji; Kobayashi, Yasuhiro [Kyoto University, Research Reactor Institute (Japan); Mitsui, Takaya [Japan Atomic Energy Agency (Japan)

2008-01-15

The unfolded heme structure in myoglobin is controversial because of no chance of direct X-ray structure analyses. The unfolding of carbonmonoxy myoglobin (MbCO) by guanidine hydrochloride (GdnHCl) was studied by the Moessbauer spectroscopy. The spectra show the presence of a sort of spectrum in the unfolded MbCO, independent on the concentration of GdnHCl from 1 to 6 M and the increase of the fraction of unfolded MbCO, depending on the GdnHCl concentration. The isomer shift of the iron of heme in the unfolded MbCO was identified to be different from that of the native MbCO as the globin structure in Mb collapses under the unfolded conditions. This result and the existing related Moessbauer data proved that the heme in the unfolded MbCO may remain coordinated to the proximal histidine.

Automation of dimethylation after guanidination labeling chemistry and its compatibility with common buffers and surfactants for mass spectrometry-based shotgun quantitative proteome analysis

Energy Technology Data Exchange (ETDEWEB)

Lo, Andy; Tang, Yanan; Chen, Lu; Li, Liang, E-mail: Liang.Li@ualberta.ca

2013-07-25

Graphical abstract: -- Highlights: •Dimethylation after guanidination (2MEGA) uses inexpensive reagents for isotopic labeling of peptides. •2MEGA can be optimized and automated for labeling peptides with high efficiency. •2MEGA is compatible with several commonly used cell lysis and protein solubilization reagents. •The automated 2MEGA labeling method can be used to handle a variety of protein samples for relative proteome quantification. -- Abstract: Isotope labeling liquid chromatography–mass spectrometry (LC–MS) is a major analytical platform for quantitative proteome analysis. Incorporation of isotopes used to distinguish samples plays a critical role in the success of this strategy. In this work, we optimized and automated a chemical derivatization protocol (dimethylation after guanidination, 2MEGA) to increase the labeling reproducibility and reduce human intervention. We also evaluated the reagent compatibility of this protocol to handle biological samples in different types of buffers and surfactants. A commercially available liquid handler was used for reagent dispensation to minimize analyst intervention and at least twenty protein digest samples could be prepared in a single run. Different front-end sample preparation methods for protein solubilization (SDS, urea, Rapigest™, and ProteaseMAX™) and two commercially available cell lysis buffers were evaluated for compatibility with the automated protocol. It was found that better than 94% desired labeling could be obtained in all conditions studied except urea, where the rate was reduced to about 92% due to carbamylation on the peptide amines. This work illustrates the automated 2MEGA labeling process can be used to handle a wide range of protein samples containing various reagents that are often encountered in protein sample preparation for quantitative proteome analysis.

Pharmacological Identification of a Guanidine-Containing β-Alanine Analogue with Low Micromolar Potency and Selectivity for the Betaine/GABA Transporter 1 (BGT1)

DEFF Research Database (Denmark)

Al-Khawaja, Anas Mohammad Ali; Petersen, Jette Gellert; Damgaard, Maria

2014-01-01

of the amino group in β-alanine or GABA, a series of compounds was generated, and their pharmacological activity assessed at human GAT subtypes. Using a cell-based [(3)H]GABA uptake assay, several selective inhibitors at human BGT1 were identified. The guanidine-containing compound 9 (2-amino-1......,4,5,6-tetrahydropyrimidine-5-carboxylic acid hydrochloride) displayed more than 250 times greater potency than the parent compound β-alanine at BGT1 and is thus the most potent inhibitor reported to date for this subtype (IC50 value of 2.5 µM). In addition, compound 9 displayed about 400, 16 and 40 times lower inhibitory...

Induction of cytoplasmic petite in yeast by guanidine hydrochloride: combined treatment with other inducing agents.

Science.gov (United States)

Villa, L L; Juliani, M H

1980-06-01

We have studied the induction of rho- mutants by guanidine hydrochloride (GuHCl) in combination with other known inducers: ethidium bromide (EB), berenil and ultraviolet light. Competition was observed when cells were simultaneously treated with optimal concentrations of EB and GuHCl; on the other hand, treatment of cells with EB in the presence of non-inducing concentrations of GuHCl resulted in the stimulation of rho- induction of EB. Furthermore, using a strain which upon treatment with high EB concentrations shows recovery of respiratory competence, the presence of GuHCl did not interfere either with the early phase of induction or with the recovery phase, but it did interfere in a competitive fashion with the final irreversible phase of EB induction. In the case of berenil, a synergistic effect was seen when cells were pretreated with GuHCl. A synergistic induction was also observed when cells were submitted to UV prior to GuHCl treatment. These results suggest that GuHCl, EB and berenil act via some common step in their rho- induction pathways. Moreover, GuHCl may somehow be decreasing the efficiency of dark repair of ultraviolet lesions on mitochondrial DNA.

Reactivity of Zinc Halide Complexes Containing Camphor-Derived Guanidine Ligands with Technical rac-Lactide

Directory of Open Access Journals (Sweden)

Angela Metz

2017-11-01

Full Text Available Three new zinc complexes with monoamine–guanidine hybridligands have been prepared, characterized by X-ray crystallography and NMR spectroscopy, and tested in the solvent-free ring-opening polymerization of rac-lactide. Initially the ligands were synthesized from camphoric acid to obtain TMGca and DMEGca and then reacted with zinc(II halides to form zinc complexes. All complexes have a distorted tetrahedral coordination. They were utilized as catalysts in the solvent-free polymerization of technical rac-lactide at 150 °C. Colorless polylactide (PLA can be produced and after 2 h conversion up to 60% was reached. Furthermore, one zinc chlorido complex was tested with different qualities of lactide (technical and recrystallized and with/without the addition of benzyl alcohol as a co-initiator. The kinetics were monitored by in situ FT-IR or 1H NMR spectroscopy. All kinetic measurements show first-order behavior with respect to lactide. The influence of the chiral complexes on the stereocontrol of PLA was examined. Moreover, with MALDI-ToF measurements the end-group of the obtained polymer was determined. DFT and NBO calculations give further insight into the coordination properties. All in all, these systems are robust against impurities and water in the lactide monomer and show great catalytic activity in the ROP of lactide.

New promising antifouling agent based on polymeric biocide polyhexamethylene guanidine molybdate.

Science.gov (United States)

Protasov, Alexander; Bardeau, Jean-Francois; Morozovskaya, Irina; Boretska, Mariia; Cherniavska, Tetiana; Petrus, Lyudmyla; Tarasyuk, Oksana; Metelytsia, Larisa; Kopernyk, Iryna; Kalashnikova, Larisa; Dzhuzha, Oleg; Rogalsky, Sergiy

2017-09-01

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m 2 ) of the total biomass on control panel surfaces. However, considerably lower Bryozoa fouling biomass (15 g/m 2 ) was detected for coatings containing PHMG molybdate. Dreissenidae mollusks were found to form 88% (2182 g/m 2 ) of the fouling biomass on the control substrates after 228 d of exposure, whereas coatings containing PHMG molybdate showed a much lower biomass value of 23.6 g/m 2 . The leaching rate of PHMG molybdate in water was found to be similar to rates for conventional booster biocides ranging from 5.7 μg/cm 2 /d at the initial stage to 2.2 μg/cm 2 /d at steady state. Environ Toxicol Chem 2017;36:2543-2551. © 2017 SETAC. © 2017 SETAC.

Effects on Energy Metabolism of Two Guanidine Molecules, (Boc)2 -Creatine and Metformin.

Science.gov (United States)

Garbati, Patrizia; Ravera, Silvia; Scarfì, Sonia; Salis, Annalisa; Rosano, Camillo; Poggi, Alessandro; Damonte, Gianluca; Millo, Enrico; Balestrino, Maurizio

2017-09-01

Several enzymes are involved in the energy production, becoming a possible target for new anti-cancer drugs. In this paper, we used biochemical and in silico studies to evaluate the effects of two guanidine molecules, (Boc) 2 -creatine and metformin, on creatine kinase, an enzyme involved in the regulation of intracellular energy levels. Our results show that both drugs inhibit creatine kinase activity; however, (Boc) 2 -creatine displays a competitive inhibition, while metformin acts with a non-competitive mechanism. Moreover, (Boc) 2 -creatine is able to inhibit the activity of hexokinase with a non-competitive mechanism. Considering that creatine kinase and hexokinase are involved in energy metabolism, we evaluated the effects of (Boc) 2 -creatine and metformin on the ATP/AMP ratio and on cellular proliferation in healthy fibroblasts, human breast cancer cells (MDA-MB-468), a human neuroblastoma cell line (SH-SY5Y), a human Hodgkin lymphoma cell line (KMH2). We found that healthy fibroblasts were only partially affected by (Boc) 2 -creatine, while both ATP/AMP ratio and viability of the three cancer cell lines were significantly decreased. By inhibiting both creatine kinase and hexokinase, (Boc) 2 -creatine appears as a promising new agent in anticancer treatment. Further research is needed to understand what types of cancer cells are most suitable to treatment by this new compound. J. Cell. Biochem. 118: 2700-2711, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Kinetic Analysis of Guanidine Hydrochloride Inactivation of β-Galactosidase in the Presence of Galactose

Directory of Open Access Journals (Sweden)

Charles O. Nwamba

2012-01-01

Full Text Available Inactivation of purified β-Galactosidase was done with GdnHCl in the absence and presence of varying [galactose] at 50°C and at pH 4.5. Lineweaver-Burk plots of initial velocity data, in the presence and absence of guanidine hydrochloride (GdnHCl and galactose, were used to determine the relevant and max values, with p-nitrophenyl β-D-galactopyranoside (pNPG as substrate, S. Plots of ln([]∞−[] against time in the presence of GdnHCl yielded the inactivation rate constant, A. Plots of A versus [S] at different galactose concentrations were straight lines that became increasingly less steep as the [galactose] increased, showing that A was dependent on [S]. Slopes and intercepts of the 1/[]∞ versus 1/[] yielded +0 and ′+0, the microscopic rate constants for the free enzyme and the enzyme-substrate complex, respectively. Plots of +0 and ′+0 versus [galactose] showed that galactose protected the free enzyme as well as the enzyme-substrate complex (only at the lowest and highest [galactose] against GdnHCl inactivation. In the absence of galactose, GdnHCl exhibited some degree of non-competitive inhibition. In the presence of GdnHCl, galactose exhibited competitive inhibition at the lower [galactose] of 5 mM which changed to non-competitive as the [galactose] increased. The implications of our findings are further discussed.

Self-assembly, foaming, and emulsifying properties of sodium alkyl carboxylate/guanidine hydrochloride aqueous mixtures.

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Fameau, Anne-Laure; Houinsou-Houssou, Bérénice; Ventureira, Jorge Luis; Navailles, Laurence; Nallet, Frédéric; Novales, Bruno; Douliez, Jean-Paul

2011-04-19

Unsaturated fatty acids may be extracted from various agricultural resources and are widely used as soaps in the industry. However, there also exist a large variety of saturated and hydroxy fatty acids in nature, but their metal salts crystallize at room temperature in water, hampering their use in biological and chemical studies or for industrial applications. Addition of guanidine hydrochloride (GuHCl) to sodium salt of myristic acid has been shown to prevent its crystallization in water, forming stable flat bilayers at room temperature. Herein, we extend this finding to two other saturated fatty acids (palmitic and stearic acids) and two hydroxyl fatty acids (juniperic and 12 hydroxy stearic acids) and study more deeply (by using small angle neutron scattering) the supramolecular assemblies formed in both saturated and hydroxyl fatty acid systems. In addition, we take the advantage that crystallization no longer occurs at room temperature in the presence of GuHCl to study the foaming and emulsifying properties of those fatty acid dispersions. Briefly, our results show that all fatty acids, even juniperic acid, which is a bola lipid, are arranged in a bilayer structure that may be interdigitated. Depending on the nature of the fatty acid, the systems exhibit good foamability and foam stability (except for juniperic acid), and emulsion stability was good. Those findings should be of interest for using saturated long chain (and hydroxyl) fatty acids as surfactants for detergency or even materials chemistry. © 2011 American Chemical Society

Probing Conformational Stability and Dynamics of Erythroid and Nonerythroid Spectrin: Effects of Urea and Guanidine Hydrochloride

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Patra, Malay; Mukhopadhyay, Chaitali; Chakrabarti, Abhijit

2015-01-01

We have studied the conformational stability of the two homologous membrane skeletal proteins, the erythroid and non-erythroid spectrins, in their dimeric and tetrameric forms respectively during unfolding in the presence of urea and guanidine hydrochloride (GuHCl). Fluorescence and circular dichroism (CD) spectroscopy have been used to study the changes of intrinsic tryptophan fluorescence, anisotropy, far UV-CD and extrinsic fluorescence of bound 1-anilinonapthalene-8-sulfonic acid (ANS). Chemical unfolding of both proteins were reversible and could be described as a two state transition. The folded erythroid spectrin and non-erythroid spectrin were directly converted to unfolded monomer without formation of any intermediate. Fluorescence quenching, anisotropy, ANS binding and dynamic light scattering data suggest that in presence of low concentrations of the denaturants (up-to 1M) hydrogen bonding network and van der Waals interaction play a role inducing changes in quaternary as well as tertiary structures without complete dissociation of the subunits. This is the first report of two large worm like, multi-domain proteins obeying twofold rule which is commonly found in small globular proteins. The free energy of stabilization (ΔGu H 2 0) for the dimeric spectrin has been 20 kcal/mol lesser than the tetrameric from. PMID:25617632

Polyhexamethylene guanidine phosphate aerosol particles induce pulmonary inflammatory and fibrotic responses.

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Kim, Ha Ryong; Lee, Kyuhong; Park, Chang We; Song, Jeong Ah; Shin, Da Young; Park, Yong Joo; Chung, Kyu Hyuck

2016-03-01

Polyhexamethylene guanidine (PHMG) phosphate was used as a disinfectant for the prevention of microorganism growth in humidifiers, without recognizing that a change of exposure route might cause significant health effects. Epidemiological studies reported that the use of humidifier disinfectant containing PHMG-phosphate can provoke pulmonary fibrosis. However, the pulmonary toxicity of PHMG-phosphate aerosol particles is unknown yet. This study aimed to elucidate the toxicological relationship between PHMG-phosphate aerosol particles and pulmonary fibrosis. An in vivo nose-only exposure system and an in vitro air-liquid interface (ALI) co-culture model were applied to confirm whether PHMG-phosphate induces inflammatory and fibrotic responses in the respiratory tract. Seven-week-old male Sprague-Dawley rats were exposed to PHMG-phosphate aerosol particles for 3 weeks and recovered for 3 weeks in a nose-only exposure chamber. In addition, three human lung cells (Calu-3, differentiated THP-1 and HMC-1 cells) were cultured at ALI condition for 12 days and were treated with PHMG-phosphate at set concentrations and times. The reactive oxygen species (ROS) generation, airway barrier injuries and inflammatory and fibrotic responses were evaluated in vivo and in vitro. The rats exposed to PHMG-phosphate aerosol particles in nanometer size showed pulmonary inflammation and fibrosis including inflammatory cytokines and fibronectin mRNA increase, as well as histopathological changes. In addition, PHMG-phosphate triggered the ROS generation, airway barrier injuries and inflammatory responses in a bronchial ALI co-culture model. Those results demonstrated that PHMG-phosphate aerosol particles cause pulmonary inflammatory and fibrotic responses. All features of fibrogenesis by PHMG-phosphate aerosol particles closely resembled the pathology of fibrosis that was reported in epidemiological studies. Finally, we expected that PHMG-phosphate infiltrated into the lungs in the form of

Highly sensitive determination of poly(hexamethylene guanidine) by Rayleigh scattering using aggregation of silver nanoparticles

International Nuclear Information System (INIS)

Artemyeva, Anastasia A.; Sharov, Andrei V.; Beklemishev, Mikhail K.; Samarina, Tatyana O.; Abramchuk, Sergei S.; Ovcharenko, Elena O.; Dityuk, Alexander I.; Efimov, Konstantin M.

2015-01-01

We have found that low concentrations of the polycationic disinfectant poly(hexamethylene guanidine) hydrochloride (PHMG) induce the aggregation of citrate-stabilized silver nanoparticles (AgNPs) in aqueous solution. Based on this finding, we have worked out a method to the determination of PHMG. The protocol includes the steps of (a) centrifuging the water sample, (b) addition of an aliquot of the colloidal solution of the AgNPs, and (c) measurement of the intensity of scattered light. The method is surprisingly selective in that comparable concentrations of surfactants, humic acids and protein do not interfere. Besides, an up to 50 mM concentration NaCl, and up to 5 mM of Mg(II) or Ca(II) are tolerated. Other cationic polyelectrolytes, polyethyleneimine and poly(dimethyldiallyammonium chloride), also cause aggregation of AgNPs but to a lesser extent. The determination of PHMG was performed in spiked samples (run-off, tap and swimming pool waters) with detection limits of 2·10 −8 , 4·10 −7 , and 6·10 −6 M (by monomer unit), respectively. The linear ranges are wider and the detection limits are lower than those of known spectrophotometric methods. It is necessary, however, to correct the calibration plot for background scattering by the sample and to establish a calibration plot for each kind of water sample. Notwithstanding this, the approach is attractive because it is sensitive, rapid, and simple. (author)

Synthesis and biological evaluation of tricyclic guanidine analogues of batzelladine K for antimalarial, antileishmanial, antibacterial, antifungal, and anti-HIV activities.

Science.gov (United States)

Ahmed, Nafees; Brahmbhatt, Keyur G; Khan, Shabana I; Jacob, Melissa; Tekwani, Babu L; Sabde, Sudeep; Mitra, Debashis; Singh, Inder P; Khan, Ikhlas A; Bhutani, Kamlesh K

2013-04-01

Fifty analogues of batzelladine K were synthesized and evaluated for in vitro antimalarial (Plasmodium falciparum), antileishmanial (Leishmania donovani), antimicrobial (panel of bacteria and fungi), antiviral (HIV-1) activities. Analogues 14h and 20l exhibited potential antimalarial activity against chloroquine-sensitive D6 strain with IC(50) 1.25 and 0.88 μM and chloroquine-resistant W2 strain with IC(50) 1.64 and 1.07 μM, respectively. Analogues 12c and 14c having nonyl substitution showed the most potent antileishmanial activity with IC(50) 2.39 and 2.78 μM and IC(90) 11.27 and 12.76 μM, respectively. Three analogues 12c, 14c, and 14i were the most active against various pathogenic bacteria and fungi with IC(50) Analogue 20l having pentyl and methyl substituents on tricycle showed promising activities against all pathogens. However, none was found active against HIV-1. Our study demonstrated that the tricyclic guanidine compounds provide new structural class for broad spectrum activity. © 2012 John Wiley & Sons A/S.

The Marine Guanidine Alkaloid Crambescidin 816 Induces Calcium Influx and Cytotoxicity in Primary Cultures of Cortical Neurons through Glutamate Receptors.

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Mendez, Aida G; Juncal, Andrea Boente; Silva, Siguara B L; Thomas, Olivier P; Martín Vázquez, Víctor; Alfonso, Amparo; Vieytes, Mercedes R; Vale, Carmen; Botana, Luís M

2017-07-19

Crambescidin 816 is a guanidine alkaloid produced by the sponge Crambe crambe with known antitumoral activity. While the information describing the effects of this alkaloid in central neurons is scarce, Cramb816 is known to block voltage dependent calcium channels being selective for L-type channels. Moreover, Cramb816 reduced neuronal viability through an unknown mechanism. Here, we aimed to describe the toxic activity of Cramb816 in cortical neurons. Since calcium influx is considered the main mechanism responsible for neuronal cell death, the effects of Cramb816 in the cytosolic calcium concentration of cortical neurons were studied. The alkaloid decreased neuronal viability and induced a dose-dependent increase in cytosolic calcium that was also related to the presence of calcium in the extracellular media. The increase in calcium influx was age dependent, being higher in younger neurons. Moreover, this effect was prevented by glutamate receptor antagonists, which did not fully block the cytotoxic effect of Cramb816 after 24 h of treatment but completely prevented Cramb816 cytotoxicity after 10 min exposure. Therefore, the findings presented herein provide new insights into the cytotoxic effect of Cramb816 in cortical neurons.

Subtype-specific Modulation of Acid-sensing Ion Channel (ASIC) Function by 2-Guanidine-4-methylquinazoline*

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Alijevic, Omar; Kellenberger, Stephan

2012-01-01

Acid-sensing ion channels (ASICs) are neuronal Na+-selective channels that are transiently activated by extracellular acidification. ASICs are involved in fear and anxiety, learning, neurodegeneration after ischemic stroke, and pain sensation. The small molecule 2-guanidine-4-methylquinazoline (GMQ) was recently shown to open ASIC3 at physiological pH. We have investigated the mechanisms underlying this effect and the possibility that GMQ may alter the function of other ASICs besides ASIC3. GMQ shifts the pH dependence of activation to more acidic pH in ASIC1a and ASIC1b, whereas in ASIC3 this shift goes in the opposite direction and is accompanied by a decrease in its steepness. GMQ also induces an acidic shift of the pH dependence of inactivation of ASIC1a, -1b, -2a, and -3. As a consequence, the activation and inactivation curves of ASIC3 but not other ASICs overlap in the presence of GMQ at pH 7.4, thereby creating a window current. At concentrations >1 mm, GMQ decreases maximal peak currents by reducing the unitary current amplitude. Mutation of residue Glu-79 in the palm domain of ASIC3, previously shown to be critical for channel opening by GMQ, disrupted the GMQ effects on inactivation but not activation. This suggests that this residue is involved in the consequences of GMQ binding rather than in the binding interaction itself. This study describes the mechanisms underlying the effects of a novel class of ligands that modulate the function of all ASICs as well as activate ASIC3 at physiological pH. PMID:22948146

Subtype-specific modulation of acid-sensing ion channel (ASIC) function by 2-guanidine-4-methylquinazoline.

Science.gov (United States)

Alijevic, Omar; Kellenberger, Stephan

2012-10-19

Acid-sensing ion channels (ASICs) are neuronal Na(+)-selective channels that are transiently activated by extracellular acidification. ASICs are involved in fear and anxiety, learning, neurodegeneration after ischemic stroke, and pain sensation. The small molecule 2-guanidine-4-methylquinazoline (GMQ) was recently shown to open ASIC3 at physiological pH. We have investigated the mechanisms underlying this effect and the possibility that GMQ may alter the function of other ASICs besides ASIC3. GMQ shifts the pH dependence of activation to more acidic pH in ASIC1a and ASIC1b, whereas in ASIC3 this shift goes in the opposite direction and is accompanied by a decrease in its steepness. GMQ also induces an acidic shift of the pH dependence of inactivation of ASIC1a, -1b, -2a, and -3. As a consequence, the activation and inactivation curves of ASIC3 but not other ASICs overlap in the presence of GMQ at pH 7.4, thereby creating a window current. At concentrations >1 mM, GMQ decreases maximal peak currents by reducing the unitary current amplitude. Mutation of residue Glu-79 in the palm domain of ASIC3, previously shown to be critical for channel opening by GMQ, disrupted the GMQ effects on inactivation but not activation. This suggests that this residue is involved in the consequences of GMQ binding rather than in the binding interaction itself. This study describes the mechanisms underlying the effects of a novel class of ligands that modulate the function of all ASICs as well as activate ASIC3 at physiological pH.

Inactivation and unfolding of protein tyrosine phosphatase from Thermus thermophilus HB27 during urea and guanidine hydrochloride denaturation.

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Yejing Wang

Full Text Available The effects of urea and guanidine hydrochloride (GdnHCl on the activity, conformation and unfolding process of protein tyrosine phosphatase (PTPase, a thermostable low molecular weight protein from Thermus thermophilus HB27, have been studied. Enzymatic activity assays showed both urea and GdnHCl resulted in the inactivation of PTPase in a concentration and time-dependent manner. Inactivation kinetics analysis suggested that the inactivation of PTPase induced by urea and GdnHCl were both monophasic and reversible processes, and the effects of urea and GdnHCl on PTPase were similar to that of mixed-type reversible inhibitors. Far-ultraviolet (UV circular dichroism (CD, Tryptophan and 1-anilinonaphthalene -8-sulfonic acid (ANS fluorescence spectral analyses indicated the existence of a partially active and an inactive molten globule-like intermediate during the unfolding processes induced by urea and GdnHCl, respectively. Based on the sequence alignment and the homolog Tt1001 protein structure, we discussed the possible conformational transitions of PTPase induced by urea and GdnHCl and compared the conformations of these unfolding intermediates with the transient states in bovine PTPase and its complex structures in detail. Our results may be able to provide some valuable clues to reveal the relationship between the structure and enzymatic activity, and the unfolding pathway and mechanism of PTPase.

MicroRNA regulatory networks reflective of polyhexamethylene guanidine phosphate-induced fibrosis in A549 human alveolar adenocarcinoma cells.

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Shin, Da Young; Jeong, Mi Ho; Bang, In Jae; Kim, Ha Ryong; Chung, Kyu Hyuck

2018-05-01

Polyhexamethylene guanidine phosphate (PHMG-phosphate), an active component of humidifier disinfectant, is suspected to be a major cause of pulmonary fibrosis. Fibrosis, induced by recurrent epithelial damage, is significantly affected by epigenetic regulation, including microRNAs (miRNAs). The aim of this study was to investigate the fibrogenic mechanisms of PHMG-phosphate through the profiling of miRNAs and their target genes. A549 cells were treated with 0.75 μg/mL PHMG-phosphate for 24 and 48 h and miRNA microarray expression analysis was conducted. The putative mRNA targets of the miRNAs were identified and subjected to Gene Ontology analysis. After exposure to PHMG-phosphate for 24 and 48 h, 46 and 33 miRNAs, respectively, showed a significant change in expression over 1.5-fold compared with the control. The integrated analysis of miRNA and mRNA microarray results revealed the putative targets that were prominently enriched were associated with the epithelial-mesenchymal transition (EMT), cell cycle changes, and apoptosis. The dose-dependent induction of EMT by PHMG-phosphate exposure was confirmed by western blot. We identified 13 putative EMT-related targets that may play a role in PHMG-phosphate-induced fibrosis according to the Comparative Toxicogenomic Database. Our findings contribute to the comprehension of the fibrogenic mechanism of PHMG-phosphate and will aid further study on PHMG-phosphate-induced toxicity. Copyright © 2018 Elsevier B.V. All rights reserved.

Fluorescent determination of poly(hexamethylene guanidine) via the aggregates it forms with quantum dots and magnetic nanoparticles

International Nuclear Information System (INIS)

Likhachev, Konstantin V.; Beklemishev, Mikhail K.; Ovcharenko, Elena O.; Dityuk, Alexander I.; Efimov, Konstantin M.; Abramchuk, Sergei S.

2016-01-01

The authors report that the cationic polymer-oligomer poly(hexamethylene guanidine) (PHMG) in the form of its hydrochloride induces the formation of mixed aggregates composed of anionic magnetic nanoparticles (magNPs), PHMG and anionic quantum dots (QDs). The magNPs consisted of polymer-coated magnetite nanoparticles, and the QDs consisted of polymer-coated CdSe-CdS/ZnS nanoparticles with an emission maximum at 617 nm. This finding is exploited in a semi-quantitative method for the determination of PHMG. The protocol includes magnetic separation of the mixed aggregates (magNPs/PHMG/QDs) from the sample and excess QDs, redispersion of the aggregates in water, and measurement of fluorescence intensity. The signal is proportional to the concentration of PHMG in the 0.05 to 0.2 mg L"−"1 concentration range, with intra-day RSDs of up to 27 %. The limit of detection (LOD) of PHMG in spiked run-off waters, swimming pool water and wastewater is 23 μg L"−"1. This PHMG assay is selective in that high concentrations of surfactants and inorganic salts are tolerated. Polyethyleneimine and poly(diallyldimethylammonium chloride) also cause the formation of mixed aggregates but only at higher concentrations. Both a fluorometer and a digital camera (using a 365-nm LED as a light source) were used to measure fluorescence. In case of using a digital camera, the LOD is 40 μg L"−"1 and the intraday RSDs are up to 23 %. The method is sensitive, fairly selective and rather simple. (author)

Dynamics of picornavirus RNA replication within infected cells

DEFF Research Database (Denmark)

Belsham, Graham; Normann, Preben

2008-01-01

Replication of many picornaviruses is inhibited by low concentrations of guanidine. Guanidine-resistant mutants are readily isolated and the mutations map to the coding region for the 2C protein. Using in vitro replication assays it has been determined previously that guanidine blocks the initiat......Replication of many picornaviruses is inhibited by low concentrations of guanidine. Guanidine-resistant mutants are readily isolated and the mutations map to the coding region for the 2C protein. Using in vitro replication assays it has been determined previously that guanidine blocks...... the initiation of negative-strand synthesis. We have now examined the dynamics of RNA replication, measured by quantitative RT-PCR, within cells infected with either swine vesicular disease virus (an enterovirus) or foot-and-mouth disease virus as regulated by the presence or absence of guanidine. Following...... the removal of guanidine from the infected cells, RNA replication occurs after a significant lag phase. This restoration of RNA synthesis requires de novo protein synthesis. Viral RNA can be maintained for at least 72 h within cells in the absence of apparent replication but guanidine-resistant virus can...

Elimination of 3H-methylguanidine at limited renal function

International Nuclear Information System (INIS)

Berger, D.G.

1976-01-01

The serum levels, hepatic and renal excretions and the tissue concentrations of 3 H methyl guanidine 60 to 90 minutes after intravenous injection were measured in rats with healthy kidneys and rats with experimental renal insufficiences. The following results were obtained: Methyl guanidine is quickly eliminated through the kidney and the liver of organisms with healthy kidneys. In the case of experimental renal insufficiency, the renal excretion of methyl guanidine is reduced, whilst the hepatic excretion is increased. Methyl guanidine is subject to an enterohepatic circuit. Methyl guanidine can accumulate to much higher levels in various tissues examined than in serum. The highest organ accumulation level of methyl guanidine was found in the case of renal insufficiency. The most important finding of the study accordingly is the partial rehabilitation of methyl guanidine as a potential uremic poison. In the author's opinion, too much attention has so far been paid to the serum concentration, and too little attention to the tissue level of the substance. (orig.) [de

Application of phosphating techniques to aluminium and carbon steel surfaces using nitro guanidine as oxidizing agent

International Nuclear Information System (INIS)

Briseno M, S.A.

1995-01-01

Phosphate coatings are inorganic crystalline deposits laid down uniformly on properly prepared surfaces by a chemical reaction with the treated base metal. The reaction consists in dissolving some surface metal by acid attack and then causing surface neutralization of the phosphate solution with consequent precipitation of the phosphate coating. Phosphate coatings do not provide appreciable corrosion protection in themselves. They are useful mainly as a base for paints, ensuring good adherence of paint to steel and decreasing the tendency for corrosion to under cut the paint film at scratches or other defects. In this work firstly were realized phosphate on standard carbon steel, employing technical of cold phosphate (at 40 Centigrade degrees and with a treatment time of 30 minutes) and hot phosphate (at 88 Centigrade degrees and with a treatment time of 15 minutes), where with this last were obtained the best results. Both methods used phosphate solutions of Zn/Mn and using as catalyst Nitro guanidine. Aluminium surfaces were phosphate used solutions of Cr and as catalyst Sodium bi fluoride. The phosphating on this surface were realized at temperature of 50 Centigrade degrees and with a treatment time of 10 minutes. In this work were obtained a new phosphate coatings on steel surfaces, these coatings were realized with a phosphate solution manufactured with the precipitates gathered during the hot phosphating on carbon steel. These coatings show excellent physical characteristics and of corrosion resistance. Were determined the physical testings of the coatings phosphate obtained on carbon steel and aluminium surfaces. These testing were: roughness, thickness, microhardness and adhesion. The best results were showed in carbon steel phosphate with precipitated solutions. The technical of analysis for activation with thermic neutrons was used to determine the phosphate coatings composition. Finally, corrosion testings were realized by means of two methods

Mass transfer ranking of polylysine, poly-ornithine and poly-methylene-co-guanidine microcapsule membranes using a single low molecular mass marker

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Rosinski Stefan

2003-01-01

Full Text Available On the long way to clinical transplantable hybrid systems, comprising of cells, acting as immuno-protected bioreactors microencapsulated in a polymeric matrix and delivering desired factors (proteins, hormones, enzymes etc to the patient's body, an important step is the optimization of the microcapsule. This topic includes the selection of a proper coating membrane which could fulfil, first of all, the mass transfer as well as biocompatibility, stability and durability requirements. Three different membranes from polymerised aminoacids, formed around exactly identical alginate gel cores, were considered, concerning their mass transport properties, as potential candidates in this task. The results of the evaluation of the mass ingress and mass transfer coefficient h for the selected low molecular mass marker, vitamin B12, in poly-L-lysine (HPLL poly-L-ornithine (HPLO and poly-methylene-co-guanidine hydrochloride (HPMCG membrane alginate microcapsules demonstrate the advantage of using the mass transfer approach to a preliminary screening of various microcapsule formulations. Applying a single marker and evaluating mass transfer coefficients can help to quickly rank the investigated membranes and microcapsules according to their permeability. It has been demonstrated that HPLL, HPLO and HPMCG microcapsules differ from each other by a factor of two concerning the rate of low molecular mass marker transport. Interesting differences in mass transfer through the membrane in both directions in-out was also found, which could possibly be related to the membrane asymmetry.

Quantitative analysis of polyhexamethylene guanidine (PHMG) oligomers via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with an ionic-liquid matrix.

Science.gov (United States)

Yoon, Donhee; Lee, Dongkun; Lee, Jong-Hyeon; Cha, Sangwon; Oh, Han Bin

2015-01-30

Quantifying polymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) with a conventional crystalline matrix generally suffers from poor sample-to-sample or shot-to-shot reproducibility. An ionic-liquid matrix has been demonstrated to mitigate these reproducibility issues by providing a homogeneous sample surface, which is useful for quantifying polymers. In the present study, we evaluated the use of an ionic liquid matrix, i.e., 1-methylimidazolium α-cyano-4-hydroxycinnamate (1-MeIm-CHCA), to quantify polyhexamethylene guanidine (PHMG) samples that impose a critical health hazard when inhaled in the form of droplets. MALDI-TOF mass spectra were acquired for PHMG oligomers using a variety of ionic-liquid matrices including 1-MeIm-CHCA. Calibration curves were constructed by plotting the sum of the PHMG oligomer peak areas versus PHMG sample concentration with a variety of peptide internal standards. Compared with the conventional crystalline matrix, the 1-MeIm-CHCA ionic-liquid matrix had much better reproducibility (lower standard deviations). Furthermore, by using an internal peptide standard, good linear calibration plots could be obtained over a range of PMHG concentrations of at least 4 orders of magnitude. This study successfully demonstrated that PHMG samples can be quantitatively characterized by MALDI-TOFMS with an ionic-liquid matrix and an internal standard. Copyright © 2014 John Wiley & Sons, Ltd.

Modified spectrophotometer for multi-dimensional circular dichroism/fluorescence data acquisition in titration experiments: application to the pH and guanidine-HCI induced unfolding of apomyoglobin.

Science.gov (United States)

Ramsay, G; Ionescu, R; Eftink, M R

1995-01-01

In a previous paper (Ramsay and Eftink, Biophys. J. 66:516-523) we reported the development of a modified spectrophotometer that can make nearly simultaneous circular dichroism (CD) and fluorescence measurements. This arrangement allows multiple data sets to be collected during a single experiment, resulting in a saving of time and material, and improved correlation between the different types of measurements. The usefulness of the instrument was shown by thermal melting experiments on several different protein systems. This CD/fluorometer spectrophotometer has been further modified by interfacing with a syringe pump and a pH meter. This arrangement allows ligand, pH, and chemical denaturation titration experiments to be performed while monitoring changes in the sample's CD, absorbance, fluorescence, and light scattering properties. Our data acquisition program also has an ability to check whether the signals have approached equilibrium before the data is recorded. For performing pH titrations we have developed a procedure which uses the signal from a pH meter in a feedback circuit in order to collect data at evenly spaced pH intervals. We demonstrate the use of this instrument with studies of the unfolding of sperm whale apomyoglobin, as induced by acid pH and by the addition of guanidine-HCI. Images FIGURE 2 PMID:8527683

Changes in expression of cytokines in polyhexamethylene guanidine-induced lung fibrosis in mice: Comparison of bleomycin-induced lung fibrosis.

Science.gov (United States)

Kim, Min-Seok; Kim, Sung-Hwan; Jeon, Doin; Kim, Hyeon-Young; Lee, Kyuhong

2018-01-15

Inhalation of polyhexamethylene guanidine (PHMG) causes irreversible pulmonary injury, such as pulmonary fibrosis. However, the mechanism underlying PHMG-induced lung injury is unclear. In this study, we compared the difference in time-dependent lung injury between PHMG- and bleomycin (BLM)-treated mice and determined cytokines involved in inducing lung injury by performing cytokine antibody array analysis. Mice were treated once with 1.8mg/kg BLM or 1.2mg/kg PHMG through intratracheal instillation and were sacrificed on days 7 and 28. Bronchoalveolar lavage fluid (BALF) analysis showed that the number of neutrophils was significantly higher in PHMG-treated mice than in BLM-treated mice on day 7. Histopathological analysis showed inflammatory cell infiltration and fibrosis mainly in the terminal bronchioles and alveoli in the lungs of PHMG- and BLM-treated mice. However, continuous macrophage infiltration in the alveolar space and bronchioloalveolar epithelial hyperplasia (BEH) were only observed in PHMG-treated mice. Cytokine antibody array analysis showed that 15 and eight cytokines were upregulated in PHMG- and BLM-treated mice, respectively, on day 7. On day 28, 13 and five cytokines were upregulated in PHMG and BLM-treated mice, respectively. In addition, the expressed cytokines between days 7 and 28 in BLM-treated mice were clearly different, but were similar in PHMG-treated mice. Consequently, between PHMG- and BLM-treated mice, we observed differences in the expression patterns and types of cytokines. These differences are considered to be a result of the inflammatory processes induced by both substances, which may mainly involve macrophage infiltration. Therefore, continuous induction of the inflammatory response by PHMG may play an important role in the development of pulmonary fibrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Unfolding studies of the cysteine protease baupain, a papain-like enzyme from leaves of Bauhinia forficata: effect of pH, guanidine hydrochloride and temperature.

Science.gov (United States)

Silva-Lucca, Rosemeire A; Andrade, Sheila S; Ferreira, Rodrigo Silva; Sampaio, Misako U; Oliva, Maria Luiza V

2013-12-24

Baupain belongs to the α+β class of proteins with a secondary structure-content of 44% α-helix, 16% β-sheet and 12% β-turn. The structural transition induced by pH was found to be noncooperative, with no important differences observed in the pH range from 3.0 to 10.5. At pH 2.0 the protein presented substantial non-native structure with strong ANS binding. Guanidine hydrochloride (GdnHCl)-induced unfolding did not change the protein structure significantly until 4.0 M, indicating the high rigidity of the molecule. The unfolding was cooperative, as seen by the sigmoidal transition curves with midpoints at 4.7±0.2 M and 5.0±0.2 M GdnHCl, as measured by CD and fluorescence spectroscopy. A red shift of 7 nm in intrinsic fluorescence was observed with 6.0 M GdnHCl. Temperature-induced unfolding of baupain was incomplete, and at least 35% of the native structure of the protein was retained, even at high temperature (90 °C). Baupain showed characteristics of a molten globule state, due to preferential ANS binding at pH 2.0 in comparison to the native form (pH 7.0) and completely unfolded (6.0 M GdnHCl) state. Combined with information about N-terminal sequence similarity, these results allow us to include baupain in the papain superfamily.

Guanidine hydrochloride denaturation of human serum albumin originates by local unfolding of some stable loops in domain III.

Science.gov (United States)

Ahmad, Basir; Ahmed, Md Zulfazal; Haq, Soghra Khatun; Khan, Rizwan Hasan

2005-06-15

The effect of guanidine hydrochloride (GnHCl) on the global stability of human serum albumin (HSA) has been studied by fluorescence and circular dichroism spectroscopic measurements. The differential stability of native conformation of three HSA domains were explored by using domain-specific ligands, hemin (domain I), chloroform (domain II), bilirubin (at domain I/domain II interface) and diazepam (domain III). GnHCl induced unfolding transition curves as monitored by probes for secondary and tertiary structures were cooperative but noncoincidental. A strong ANS binding to the protein was observed around 1.8 M GnHCl, suggesting existence of intermediate states in the unfolding pathway of HSA. A gradual decrease (in the GnHCl concentration range 0.0-1.8 M) in the binding of diazepam indicates that domain III is the most labile to GnHCl denaturation. A significant increase in the binding of bilirubin up to 1.4 M GnHCl and decrease thereafter leading to complete abolishment of bilirubin binding at around 2.0 M GnHCl suggest favorable rearrangement and separation of domains I and II at 1.4 and 2.0 M GnHCl concentration, respectively. Above 1.6 M GnHCl, decrease of the binding of hemin, a ligand for domain I, chloroform, which binds in domain II and lone tryptophanyl fluorescence (Trp-214 located in domain II) indicate that at higher concentration of GnHCl domains I and II start unfolding simultaneously but the stability of domain I (7.4 Kcal/mol) is much more than domain II (4.3 Kcal/mol). A pictorial model for the unfolding of HSA domains, consistent with all these results, has been formulated, suggesting that domain III is the most labile followed by domain II while domain I is the most stable. A molten globule like state of domain III around 1.8 M GnHCl has also been identified and characterized.

Unfolding Studies of the Cysteine Protease Baupain, a Papain-Like Enzyme from Leaves of Bauhinia forficata: Effect of pH, Guanidine Hydrochloride and Temperature

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Rosemeire A. Silva-Lucca

2013-12-01

Full Text Available Baupain belongs to the α+β class of proteins with a secondary structure-content of 44% α-helix, 16% β-sheet and 12% β-turn. The structural transition induced by pH was found to be noncooperative, with no important differences observed in the pH range from 3.0 to 10.5. At pH 2.0 the protein presented substantial non-native structure with strong ANS binding. Guanidine hydrochloride (GdnHCl-induced unfolding did not change the protein structure significantly until 4.0 M, indicating the high rigidity of the molecule. The unfolding was cooperative, as seen by the sigmoidal transition curves with midpoints at 4.7 ± 0.2 M and 5.0 ± 0.2 M GdnHCl, as measured by CD and fluorescence spectroscopy. A red shift of 7 nm in intrinsic fluorescence was observed with 6.0 M GdnHCl. Temperature-induced unfolding of baupain was incomplete, and at least 35% of the native structure of the protein was retained, even at high temperature (90 °C. Baupain showed characteristics of a molten globule state, due to preferential ANS binding at pH 2.0 in comparison to the native form (pH 7.0 and completely unfolded (6.0 M GdnHCl state. Combined with information about N-terminal sequence similarity, these results allow us to include baupain in the papain superfamily.

Human exposure to polyhexamethylene guanidine phosphate from humidifiers in residential settings: Cause of serious lung disease.

Science.gov (United States)

Lee, Ji Hyun; Yu, Il Je

2017-11-01

Exposure to the humidifier disinfectant, polyhexamethylene guanidine phosphate (PHMG), in mists generated from ultrasonic humidifiers was studied in a simulation chamber and apartment rooms. PHMG is suspected as a causative agent of lung disease in Korea residences. In the simulation-chamber study, the amount of disinfectant discharged from three different ultrasonic humidifiers was measured. Mists generated at 1, 2, and 4 times the recommended amount of disinfectant were sampled with an impinger, and the effect of relative humidity (RH) on airborne disinfectant concentration was studied by changing RH from 60%-70% to 90%-100%. In addition, particle size distribution (PSD) in mists was measured by scanning mobility particle sizer (SMPS), aerodynamic particle sizer (APS), and Mastersizer. In the apartment study, mists generated from ultrasonic humidifiers were sampled for 6 h in small and large rooms during fall ( n = 10) and winter ( n = 15). In the simulation study, the humidifiers discharged 205 ± 24.6 ml/h of mist at maximum capacity. Concentrations of airborne disinfectant increased with increasing concentration of disinfectant. RH affected airborne disinfectant concentration in the chamber, with increasing concentration with increasing RH. Below RH 70%, no airborne PHMG was detected. PHMG-containing mists generated from ultrasonic humidifier showed various sizes ranging from 149-157 nm to 690-740 nm to larger than 5.4 µm by SMPS, APS, and Mastersizer, respectively. Surface area mean diameter measured by Mastersizer ranged from 5.39 µm to 5.72 µm. In the apartment study conducted during the fall, the geometric mean (GM) and geometric standard deviation (GSD) and arithmetic mean (AM) and standard deviation (SD) of airborne PHMG concentration were 3.22 + 5.13 µg/m 3 and 8.26 ± 12.18 µg/m 3 , respectively. In the winter, GM + GSD and AM ± SD of airborne PHMG concentration were 0.21 + 2.11 µg/m 3 and 0.35 ± 0.62 µg/m 3 , respectively. RH and temperature

Contribution towards ALD and MOCVD of rare earth oxides and hafnium oxide. From precursor evaluation to process development and thin film characterization

International Nuclear Information System (INIS)

Xu, Ke

2013-01-01

This PhD thesis is consisted of two major parts: precursor development for ALD and MOCVD applications as well as thin film deposition using ALD and MOCVD with self developed precursors. The first part of this work presents the synthesis, characterization and detailed thermal property investigations of different novel group IV and rare earth precursor classes (guandinate, guanidine and ketoiminate). The second part of this work presents the ALD and MOCVD depositions using various guanidinate precursors for forming corresponding metal oxide thin films. The overall motivation of this work is to fulfill the lack of precursors of rare earth and group IV elements for ALD and MOCVD applications that satisfy the stringent requirements for the modern microelectronic and optoelectronic technologies. The aspect of the precursor engineering part is focusing on influence of ligand sphere on precursors' chemical and thermal properties. In this way, we successfully introduced guanidine and ketoiminate as potential ligands for the precursor design. The thin film deposition part of this work is ALD of rare earth oxides and group IV oxides employing literature known compounds which were previously developed in our research group. The main focus was dedicated to the process optimization, the characterization of the structural, morphological, compositional and functional properties of the deposited thin films. Certain film properties were discussed comparatively with the corresponding thin films deposited with literature known precursors. It was already shortly demonstrated in Chapter 6 that the guanidine ligand showed potential interest as suitable ligand for precursor engineering. This titan guanidine precursor [Ti(NC(NMe 2 ) 2 ) 4 ] (GD1) possesses higher thermal stability compared to its parent amide, [Ti(NMe 2 ) 4 ], while reactivity against water is not significantly affected. It could be very interesting to transfer this ligand for the precursor development of rare earth

The role of NF-κB signaling pathway in polyhexamethylene guanidine phosphate induced inflammatory response in mouse macrophage RAW264.7 cells.

Science.gov (United States)

Kim, Ha Ryong; Shin, Da Young; Chung, Kyu Hyuck

2015-03-04

Polyhexamethylene guanidine (PHMG) phosphate is a competitive disinfectant with strong antibacterial activity. However, epidemiologists revealed that inhaled PHMG-phosphate may increase the risk of pulmonary fibrosis associated with inflammation, resulting in the deaths of many people, including infants and pregnant women. In addition, in vitro and in vivo studies reported the inflammatory effects of PHMG-phosphate. Therefore, the aim of the present study was to clarify the inflammatory effects and its mechanism induced by PHMG-phosphate in murine RAW264.7 macrophages. Cell viability, inflammatory cytokine secretion, nuclear factor kappa B (NF-κB) activation, and reactive oxygen species (ROS) generation were investigated in macrophages exposed to PHMG-phosphate. PHMG-phosphate induced dose-dependent cytotoxicity, with LC50 values of 11.15-0.99mg/ml at 6 and 24h, respectively. PHMG-phosphate induced pro-inflammatory cytokines including IL-1β, IL-6, and IL-8. In particular, IL-8 expression was completely inhibited by the NF-κB inhibitor BAY11-7082. In addition, PHMG-phosphate decreased IκB-α protein expression and increased NF-κB-mediated luciferase activity, which was diminished by N-acetyl-l-cystein. However, abundant amounts of ROS were generated in the presence of PHMG-phosphate at high concentrations with a cytotoxic effect. Our results demonstrated that PHMG-phosphate triggered the activation of NF-κB signaling pathway by modulating the degradation of IκB-α. Furthermore, the NF-κB signaling pathway plays a critical role in the inflammatory responses induced by PHMG-phosphate. We assumed that ROS generated by PHMG-phosphate were associated with inflammatory responses as secondary mechanism. In conclusion, we suggest that PHMG-phosphate induces inflammatory responses via NF-κB signaling pathway. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Labeling by [3H]1,3-di(2-tolyl)guanidine of two high affinity binding sites in guinea pig brain: Evidence for allosteric regulation by calcium channel antagonists and pseudoallosteric modulation by sigma ligands

International Nuclear Information System (INIS)

Rothman, R.B.; Reid, A.; Mahboubi, A.; Kim, C.H.; De Costa, B.R.; Jacobson, A.E.; Rice, K.C.

1991-01-01

Equilibrium binding studies with the sigma receptor ligand [ 3 H]1,3-di(2-tolyl)guanidine ([ 3 H]DTG) demonstrated two high affinity binding sites in membranes prepared from guinea pig brain. The apparent Kd values of DTG for sites 1 and 2 were 11.9 and 37.6 nM, respectively. The corresponding Bmax values were 1045 and 1423 fmol/mg of protein. Site 1 had high affinity for (+)-pentazocine, haloperidol, (R)-(+)-PPP, carbepentane, and other sigma ligands, suggesting a similarity with the dextromethorphan/sigma 1 binding site described by Musacchio et al. [Life Sci. 45:1721-1732 (1989)]. Site 2 had high affinity for DTG and haloperidol (Ki = 36.1 nM) and low affinity for most other sigma ligands. Kinetic experiments demonstrated that [ 3 H]DTG dissociated in a biphasic manner from both site 1 and site 2. DTG and haloperidol increased the dissociation rate of [ 3 H]DTG from site 1 and site 2, demonstrating the presence of pseudoallosteric interactions. Inorganic calcium channel blockers such as Cd2+ selectively increased the dissociation rate of [ 3 H]DTG from site 2, suggesting an association of this binding site with calcium channels

Desenvolvimento de abordagem objetivando a síntese da 3-desidroxi-4-metoxi-tubastrina Development of an approach for the synthesis of 3-dehydroxy-4methoxy tubastrine

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Kelly de Oliveira Santos

2007-01-01

Full Text Available We report the synthesis of amino(2-hydroxy-2-(4-methoxyphenylethylaminomethaniminium (14 as a direct precursor of a tubastrine derivative (3-dehydroxy-4-methoxytubastrine. The synthetic steps involved functional group interconversions starting from 1-(4-methoxyphenylethanone to obtain the guanidine-protected derivative 13. Tentative dehydration of 13 with SiOH-adsorbed CuSO4 resulted in guanidine deprotection only. This was an unexpected result, since there are no reports of CuSO4.SiOH as Boc-deprotecting of guanidines. The product 14 was obtained in five steps and 5.4 % overall yield, and constitutes a direct precursor of 3-dehydroxy-4-methoxytubastrine.

Development of an approach for the synthesis of 3-dehydroxy-4methoxy tubastrine

International Nuclear Information System (INIS)

Santos, Kelly de Oliveira; Craveiro, Marcus Vinicius; Berlinck, Roberto G.S.

2007-01-01

We report the synthesis of amino(2-hydroxy-2-(4-methoxy phenyl)ethylamino)methaniminium (14) as a direct precursor of a tubastrine derivative (3-dehydroxy-4-methoxy tubastrine). The synthetic steps involved functional group interconversions starting from 1-(4-methoxy phenyl)ethanone to obtain the guanidine-protected derivative 13. Tentative dehydration of 13 with SiOH-adsorbed CuSO 4 resulted in guanidine deprotection only. This was an unexpected result, since there are no reports of CuSO 4 .SiOH as Boc-deprotecting of guanidines. The product 14 was obtained in five steps and 5.4 % overall yield, and constitutes a direct precursor of 3-dehydroxy-4-methoxy tubastrine. (author)

Labeling by ( sup 3 H)1,3-di(2-tolyl)guanidine of two high affinity binding sites in guinea pig brain: Evidence for allosteric regulation by calcium channel antagonists and pseudoallosteric modulation by sigma ligands

Energy Technology Data Exchange (ETDEWEB)

Rothman, R.B.; Reid, A.; Mahboubi, A.; Kim, C.H.; De Costa, B.R.; Jacobson, A.E.; Rice, K.C. (National Institute of Mental Health, Bethesda, MD (USA))

1991-02-01

Equilibrium binding studies with the sigma receptor ligand ({sup 3}H)1,3-di(2-tolyl)guanidine (({sup 3}H)DTG) demonstrated two high affinity binding sites in membranes prepared from guinea pig brain. The apparent Kd values of DTG for sites 1 and 2 were 11.9 and 37.6 nM, respectively. The corresponding Bmax values were 1045 and 1423 fmol/mg of protein. Site 1 had high affinity for (+)-pentazocine, haloperidol, (R)-(+)-PPP, carbepentane, and other sigma ligands, suggesting a similarity with the dextromethorphan/sigma 1 binding site described by Musacchio et al. (Life Sci. 45:1721-1732 (1989)). Site 2 had high affinity for DTG and haloperidol (Ki = 36.1 nM) and low affinity for most other sigma ligands. Kinetic experiments demonstrated that ({sup 3}H)DTG dissociated in a biphasic manner from both site 1 and site 2. DTG and haloperidol increased the dissociation rate of ({sup 3}H)DTG from site 1 and site 2, demonstrating the presence of pseudoallosteric interactions. Inorganic calcium channel blockers such as Cd2+ selectively increased the dissociation rate of ({sup 3}H)DTG from site 2, suggesting an association of this binding site with calcium channels.

Alterations of 86Rb+ fluxes in poliovirus-infected HeLa cells and their dependence on virus replication

International Nuclear Information System (INIS)

Schaefer, A.; Geck, P.; Zibirre, R.; Kuehne, J.; Koch, G.

1984-01-01

Components of the 86Rb+ influx were investigated subsequent to poliovirus infection in the presence and absence of guanidine-HCl, both under normal steady-state conditions and after Na+ preloading of the cells. Measurements of the ouabain-sensitive 86Rb+ uptake indicated a biphasic change in the activity of the Na+, K+ pump in the course of virus infection: a transient increase in the second hour postinfection, that was detectable only after Na+ preloading and inhibition after 3 hr. The enhanced activity of the Na+, K+ pump was not affected, while the decrease later was fully prevented by the antiviral agent guanidine-HCl. The piretanide-sensitive 86Rb+ uptake due to the Na+, K+, 2 Cl- cotransport system also became strongly inhibited beginning in the second hour postinfection. The inhibition of this transport system was partially antagonized by guanidine-HCl. The remaining 86Rb+ influx in the presence of ouabain and piretanide increased in the third hour postinfection. The latter change in 86Rb+ influx, indicating an increased permeability to monovalent cations was completely abolished by guanidine-HCl

Differences in the curing of [PSI+] prion by various methods of Hsp104 inactivation.

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Yang-Nim Park

Full Text Available [PSI(+] yeast, containing the misfolded amyloid conformation of Sup35 prion, is cured by inactivation of Hsp104. There has been controversy as to whether inactivation of Hsp104 by guanidine treatment or by overexpression of the dominant negative Hsp104 mutant, Hsp104-2KT, cures [PSI(+] by the same mechanism- inhibition of the severing of the prion seeds. Using live cell imaging of Sup35-GFP, overexpression of Hsp104-2KT caused the foci to increase in size, then decrease in number, and finally disappear when the cells were cured, similar to that observed in cells cured by depletion of Hsp104. In contrast, guanidine initially caused an increase in foci size but then the foci disappeared before the cells were cured. By starving the yeast to make the foci visible in cells grown with guanidine, the number of cells with foci was found to correlate exactly with the number of [PSI(+] cells, regardless of the curing method. Therefore, the fluorescent foci are the prion seeds required for maintenance of [PSI(+] and inactivation of Hsp104 cures [PSI(+] by preventing severing of the prion seeds. During curing with guanidine, the reduction in seed size is an Hsp104-dependent effect that cannot be explained by limited severing of the seeds. Instead, in the presence of guanidine, Hsp104 retains an activity that trims or reduces the size of the prion seeds by releasing Sup35 molecules that are unable to form new prion seeds. This Hsp104 activity may also occur in propagating yeast.

Proceedings of the Annual Conference on Environmental Toxicology (8th) held at Dayton, OH, 4-6 October 1977

Science.gov (United States)

1977-12-01

methadone was 0.03 mg/dl. Alcohol and methadone were contributory to the accident. Limited chest and bone injuries and the carbon monoxide were insufficient...membrane proteins labeled with fluorocitrate in the presence of guanidine hydrochloride . Membrane vesicles (2 mg protein) were incubated with 𔃾C...solubilized in 8 M guanidine hydrochloride , 50 mM Tris-HCl, pH 7.2, and applied to a Sephadex G-50 (medium) column (0.95 x 50 cm), equilibrated and

US Army Medical Bioengineering Research and Development Laboratory Annual Progress Report for FY 84. Volume 1

Science.gov (United States)

1984-10-01

guanidIne nitrate, is biodegraded slowly in surface waters alone and relatively rapidly if present with metabolizable carbon, in which case the compound...Operation." AORN Journal 40 (1984):330. Goethals, Gerald B. "So, You Want to be in Movies ?" Today’s OR Nurse 6 (1984):36-37. Goyal, Sagar M., S.A. Schaub...Development Laboratory MR 8-84 (May 1984). Mitchell, Wayne R. Preliminarx Results of Biodegradation Studies for Guanidine Nitrate. US Army Medical

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

Science.gov (United States)

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.

Application of phosphating techniques to aluminium and carbon steel surfaces using nitro guanidine as oxidizing agent.; Aplicacion de tecnicas de fosfatacion sobre acero al carbon y aluminio, utilizando como agente oxidante la nitroguanidina.

Energy Technology Data Exchange (ETDEWEB)

Briseno M, S A

1995-10-01

Phosphate coatings are inorganic crystalline deposits laid down uniformly on properly prepared surfaces by a chemical reaction with the treated base metal. The reaction consists in dissolving some surface metal by acid attack and then causing surface neutralization of the phosphate solution with consequent precipitation of the phosphate coating. Phosphate coatings do not provide appreciable corrosion protection in themselves. They are useful mainly as a base for paints, ensuring good adherence of paint to steel and decreasing the tendency for corrosion to under cut the paint film at scratches or other defects. We deposited phosphate on standard carbon steel, employing techniques of cold phosphate (at 40 Centigrade degrees and with a treatment time of 30 minutes) and hot phosphate (at 88 Centigrade degrees and with a treatment time of 15 minutes), where the latter gave the best results. Both methods used phosphate solutions of Zn/Mn and the catalyst Nitro guanidine. Aluminium surfaces of phosphate were used solutions of Cr and as catalyst Sodium bi fluoride. The phosphating on this surface we deposited at temperature of 50 degrees C with a treatment time of 10 minutes. We obtained a new phosphate coating on steel surfaces, these coatings were realized with a phosphate solution manufactured with the precipitates gathered during the hot phosphating on carbon steel. These coatings show excellent physical characteristics of corrosion resistance. The physical testings of the coatings phosphate obtained on carbon steel and aluminium surfaces. These testing were: roughness, thickness, microhardness and adhesion. The best results were showed in carbon steel phosphate with precipitated solutions. Activation analysis with thermic neutrons was used to determine the phosphate coatings composition. Finally, corrosion testings were realized by means of two methods; electrochemical and by weight loss methods (gravimetric). (Abstract Truncated)

Magnetic polymer-silica composites as bioluminescent sensors for bilirubin detection

Energy Technology Data Exchange (ETDEWEB)

Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, pros. Lenina, 30, Tomsk (Russian Federation); Solomonov, Alexey V. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation); Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001 (Israel); Kumagai, Akiko; Miyawaki, Atsushi [Cell Function Dynamics, Brain Science Institute RIKEN, 2-1 Hirosawa, Wako-city, Saitama, 351-0198 (Japan); Khashirova, Svetlana Yu; Zhansitov, Azamat [Kabardino-Balkar State University, 173 Chernyshevskogo St., Nal' chik, 360004, Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation)

2016-11-01

The synthesis of multifunctional nano-sized materials is leading to the rapid development of key application, including improved drug delivery, bioimaging and protein separation. In this work, magnetic silica particles modified with novel guanidine containing co-polymers were manufactured via sol-gel method. To evaluate the chemical composition of our prepared samples, FT-IR spectroscopy and thermogravimetry were conducted. Scanning electron microscopy was used in order to investigate the morphology of final products after modification by guanidine containing co-polymers and iron nanoparticles. In addition, the surface of polymer-silica composites was functionalized by the novel bilirubin-inducible fluorescent protein UnaG. In an aqueous bilirubin solution, the silica particles decorated with the polymer-UnaG have showed bright fluorescence. Synthesis and characterization of these hybrid materials allow developing of new multifunctional nano-sized materials, which will be used for detection and separation of bilirubin, a lipophilic heme catabolite that is a clinical diagnostic for liver function. - Highlights: • Novel magnetic silicas grafted by guanidine containing co-polymers were prepared. • Unag protein was effectively loaded into polymer coated silicas. • The fluorescent properties depend on content of bilirubin.

Renaturation of the androgen receptor after denaturation in SDS

International Nuclear Information System (INIS)

Johnson, M.P.; Young, C.Y.F.; Rowley, D.R.; Tindall, D.J.

1986-01-01

Renaturation of the steroid binding activity of receptor proteins is a potentially useful tool for their purification and analysis. Cytosol was prepared from rat Dunning prostate tumor in buffer containing molybdate and then denatured by addition of SDS buffer and heating. Aliquots were precipitated in cold acetone and the resulting pellets were washed and solubilized with a small volume of solution containing a chaotropic agent such as 6M guanidine, 8M urea, or 5M sodium iodide. After a 20-minute incubation, samples were diluted 20-fold with buffer containing 4nM [ 3 H]dihydrotestosterone with or without excess unlabeled dihydrotestosterone. Diluted samples were incubated at 0 0 C for varying periods of time prior to assay of bound radioactivity using hydroxylapatite. A time-course of renaturation after exposure to guanidine showed a steady increase of specific binding activity during the first 7 hrs post-dilution that remained stable up to 22 hrs. Experiments with guanidine consistently demonstrated that 25-50% of binding activity was recoverable. Preliminary results using urea or sodium iodide were similar. Efforts to optimize recovery and to characterize the renatured androgen receptor are in progress

Magnetic polymer-silica composites as bioluminescent sensors for bilirubin detection

International Nuclear Information System (INIS)

Timin, Alexander S.; Solomonov, Alexey V.; Kumagai, Akiko; Miyawaki, Atsushi; Khashirova, Svetlana Yu; Zhansitov, Azamat; Rumyantsev, Evgeniy V.

2016-01-01

The synthesis of multifunctional nano-sized materials is leading to the rapid development of key application, including improved drug delivery, bioimaging and protein separation. In this work, magnetic silica particles modified with novel guanidine containing co-polymers were manufactured via sol-gel method. To evaluate the chemical composition of our prepared samples, FT-IR spectroscopy and thermogravimetry were conducted. Scanning electron microscopy was used in order to investigate the morphology of final products after modification by guanidine containing co-polymers and iron nanoparticles. In addition, the surface of polymer-silica composites was functionalized by the novel bilirubin-inducible fluorescent protein UnaG. In an aqueous bilirubin solution, the silica particles decorated with the polymer-UnaG have showed bright fluorescence. Synthesis and characterization of these hybrid materials allow developing of new multifunctional nano-sized materials, which will be used for detection and separation of bilirubin, a lipophilic heme catabolite that is a clinical diagnostic for liver function. - Highlights: • Novel magnetic silicas grafted by guanidine containing co-polymers were prepared. • Unag protein was effectively loaded into polymer coated silicas. • The fluorescent properties depend on content of bilirubin.

A microsystem to evaluate the synthesis of [3H]leucine labeled proteins by macrophages

International Nuclear Information System (INIS)

Varesio, L.; Eva, A.

1980-01-01

A method is described for evaluating protein synthesis by adherent MPHI by measuring the incorporation of [ 3 H]leucine into TCA precipitable material. By using guanidine-HCl it was possible to remove completely the radiolabeled proteins from the adherent cells that were cultured in microwells, and retain TCA precipitable material. This procedure enabled the authors to harvest the TCA precipitable proteins with a semiautomatic cell harvester. The guanidine-HCl treatment did not affect the recovery of the radioactive proteins and did not alter the sensitivity of the assay. This method is very simple and rapid and, since it is suitable for processing microcultures, permits detailed studies on the biology of small numbers of MPHI. (Auth.)

High-quality total RNA isolation from melon (Cucumis melo L. fruits rich in polysaccharides

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Gabrielle Silveira de Campos

2017-08-01

Full Text Available Melon, a member of the family Cucurbitaceae, is the fourth most important fruit in the world market and, on a volume basis, is Brazil’s main fresh fruit export. Many molecular techniques used to understand the maturation of these fruits require high concentrations of highly purified RNA. However, melons are rich in polyphenolic compounds and polysaccharides, which interfere with RNA extraction. This study aimed to determine the most appropriate method for total RNA extraction from melon fruits. Six extraction buffers were tested: T1 guanidine thiocyanate/phenol/chloroform; T2 sodium azide/?-mercaptoethanol; T3 phenol/guanidine thiocyanate; T4 CTAB/PVP/?-mercaptoethanol; T5 SDS/sodium perchlorate/PVP/?-mercaptoethanol, and T6 sarkosyl/PVP/guanidine thiocyanate, using the AxyPrepTM Multisource Total RNA Miniprep Kit. The best method for extracting RNA from both mature and green fruit was based on the SDS/PVP/?-mercaptoethanol buffer, because it rapidly generated a high quality and quantity of material. In general, higher amounts of RNA were obtained from green than mature fruits, probably due to the lower concentration of polysaccharides and water. The purified material can be used as a template in molecular techniques, such as microarrays, RT-PCR, and in the construction of cDNA and RNA-seq data.

Penelitian pengaruh variasi China clay dan napthenoc oil terhadap kekerasan dan ketahanan sobek kompon karet untuk lis pintu almari es

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Sri Brataningsih Puji Lestari

1995-06-01

Full Text Available The aim of this research is to know influence of naphthenic oil and filler china clay to the physical properties of hardness and tear resistant rubber compound for refrigerator gasket. It makes from natural rubber (pale crepe and synthetic rubber (SBR 1502 as material with addition ingredients are china clay, stearic, guanidine, naphthenic oil, paraffin wax, coumarone resin, zink okside, stearic acid, guanidine, sulfonamide, ASOP, titan diokside, brown factice and sulphur. Rubber compound for refrigerator gasket, formed to slab by hydraulic press at 150C and 150 kg/cm2. Than tasted hardness and tear resistant. The result of this research indicated naphthenic oil and filler china clay variation are high significant to hardness and tear resistant properties of rubber compound for refrigerator gasket.

[Determination of 5 nucleosides components in culture of Paecilomyces hepialid by HPLC].

Science.gov (United States)

Yang, Dan; Ma, Yun-shu; Huang, Ting-ting; Chen, Cheng

2015-08-01

The concentration of 5 nucleosides, uracil, uridine, guanidine, adenine and adenosine in culture of Paecilomyces hepialid was determined by the developed method of HPLC. The HPLC method was performed on a Waters SunFire C18 (4.6 mm x 250 mm, 5 μm) column with methanol-water gradient elution as the mobile phase. The detection wavelength was 260 nm and the colunmn temperature was controlled at 30 °C. The linear range was 10.00-200.00 mg · L(-1) (r = 0.9994) for uracil, 10.10-202.00 mg · L(-1) (r = 0.9992) for uridine, 10.00-200.00 mg · L(-1) (r = 0.9991) for guanidine, 10.30-206.00 mg · L(-1) (r = 0.9992) for adenine and 10.45-209.00 mg · L(-1) (r = 0.9991) for adenosine, respectively. The RSD of precision was 0.032%, 0.035%, 0.039%, 0.049%, 0.00080%, respectively. The average recoveries of uracil, guanidine, adenine, and adenosine were 97.34%, 99.10%, 101.6%, 98.61% and 100.2% with RSD of 1.3%, 2.1%, 0.96%, 0.95%, and 1.3% respectively. The method showed high sensitivity, good selectivity, linearity and repeatability, which was suitable for the content analysis of 5 nucleosides components in P. hepialid and its extracts.

Cooperative unfolding of apolipoprotein A-1 induced by chemical denaturation.

Science.gov (United States)

Eckhardt, D; Li-Blatter, X; Schönfeld, H-J; Heerklotz, H; Seelig, J

2018-05-25

Apolipoprotein A-1 (Apo A-1) plays an important role in lipid transfer and obesity. Chemical unfolding of α-helical Apo A-1 is induced with guanidineHCl and monitored with differential scanning calorimetry (DSC) and CD spectroscopy. The unfolding enthalpy and the midpoint temperature of unfolding decrease linearly with increasing guanidineHCl concentration, caused by the weak binding of denaturant. At room temperature, binding of 50-60 molecules guanidineHCl leads to a complete Apo A-1 unfolding. The entropy of unfolding decreases to a lesser extent than the unfolding enthalpy. Apo A-1 chemical unfolding is a dynamic multi-state equilibrium that is analysed with the Zimm-Bragg theory modified for chemical unfolding. The chemical Zimm-Bragg theory predicts the denaturant binding constant K D and the protein cooperativity σ. Chemical unfolding of Apo A-1 is two orders of magnitude less cooperative than thermal unfolding. The free energy of thermal unfolding is ~0.2 kcal/mol per amino acid residue and ~1.0 kcal/mol for chemical unfolding at room temperature. The Zimm-Bragg theory calculates conformational probabilities and the chemical Zimm-Bragg theory predicts stretches of α-helical segments in dynamic equilibrium, unfolding and refolding independently and fast. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Chemistry of clothianidin and related compounds.

Science.gov (United States)

Uneme, Hideki

2011-04-13

Clothianidin, a neonicotinoid insecticide, has been found by former Agro Division, Takeda Chemical Industries, Ltd. (Sumitomo Chemical Co., Ltd., at present) and codeveloped with Bayer CropScience. During the studies on neonicotinoid insecticides, nitenpyram (an open-chain nitromethylene derivative) was prepared first, showing a potent activity against Hemiptera and Thysanoptera pests, and its modification led to clothianidin (a nitroguanidine derivative). Clothianidin exhibits excellent control efficacies in small amounts for a wide variety of insect pests such as Hemiptera, Thysanoptera, Coleoptera, Lepidoptera, and Diptera for the long term, with excellent systemic action and by a variety of application methods. The structural features of clothianidin are a thiazole ring and an open-chain guanidine skeleton. The structure-activity relationships of guanidine derivatives and the synthetic studies of clothianidin are also discussed.

MOCVD and ALD of rare earth containing multifunctional materials. From precursor chemistry to thin film deposition and applications

International Nuclear Information System (INIS)

Milanov, Andrian Petrov

2010-01-01

The present thesis deals with the development of metal-organic complexes of rare elements. They should be used as novel precursors for the production of rare earth thin films by metal-organic chemical vapor deposition (MOCVD) and Atomic Layer Deposition (ALD). Within the work two precursor classes were examined, the tris-Malonato-complexes as well as the tris-Guanidinato-complexes of a series of rare earth metals. The latter showed excellent properties regarding to their volatility, their thermal stability, the defined decomposition and high reactivity towards water. They have been successfully used as precursors for the MOCVD of rare earth oxide layers. By using of a gadolinium guanidinate it could also be shown that the rare earth guanidinates are promising precursors for ALD of rare earth oxide and MOCVD of rare earth nitride layers. [de

Asymmetric H-D exchange reactions of fluorinated aromatic ketones

KAUST Repository

Zhao, Yujun; Lim, XiaoZhi; Pan, Yuanhang; Zong, Lili; Feng, Wei; Tan, Choonhong; Huang, Kuo-Wei

2012-01-01

Chiral bicyclic guanidine catalyzes the asymmetric H-D exchange reactions. Up to 30% ee was achieved. DFT calculations were employed to elucidate and explain the origin of the reaction's stereoselectivity. © 2012 The Royal Society of Chemistry.

Electrostatic interactions play an essential role in the binding of oleic acid with α-lactalbumin in the HAMLET-like complex: a study using charge-specific chemical modifications.

Science.gov (United States)

Xie, Yongjing; Min, Soyoung; Harte, Níal P; Kirk, Hannah; O'Brien, John E; Voorheis, H Paul; Svanborg, Catharina; Hun Mok, K

2013-01-01

Human α-lactalbumin made lethal to tumor cells (HAMLET) and its analogs are partially unfolded protein-oleic acid (OA) complexes that exhibit selective tumoricidal activity normally absent in the native protein itself. To understand the nature of the interaction between protein and OA moieties, charge-specific chemical modifications of lysine side chains involving citraconylation, acetylation, and guanidination were employed and the biophysical and biological properties were probed. Upon converting the original positively-charged lysine residues to negatively-charged citraconyl or neutral acetyl groups, the binding of OA to protein was eliminated, as were any cytotoxic activities towards osteosarcoma cells. Retention of the positive charges by converting lysine residues to homoarginine groups (guanidination); however, yielded unchanged binding of OA to protein and identical tumoricidal activity to that displayed by the wild-type α-lactalbumin-oleic acid complex. With the addition of OA, the wild-type and guanidinated α-lactalbumin proteins underwent substantial conformational changes, such as partial unfolding, loss of tertiary structure, but retention of secondary structure. In contrast, no significant conformational changes were observed in the citraconylated and acetylated α-lactalbumins, most likely because of the absence of OA binding. These results suggest that electrostatic interactions between the positively-charged basic groups on α-lactalbumin and the negatively-charged carboxylate groups on OA molecules play an essential role in the binding of OA to α-lactalbumin and that these interactions appear to be as important as hydrophobic interactions. Copyright © 2012 Wiley Periodicals, Inc.

Low buoyant density proteoglycans from saline and dissociative extracts of embryonic chicken retinas

Energy Technology Data Exchange (ETDEWEB)

Morris, J.E.; Ting, Y.P.; Birkholz-Lambrecht, A.

1984-03-01

Retinas were labeled in culture with (/sup 3/H)glucosamine or (/sup 3/H)leucine and (/sup 35/S)sulfate and extracted sequentially with physiologically balanced saline and 4 M guanidine HCl. They were dialyzed into associative conditions (0.5 M NaCl) and chromatographed on agarose columns. Under these conditions, some of the proteoglycans were associated in massive complexes that showed low buoyant densities when centrifuged in CsCl density gradients under dissociative conditions (4 M guanidine HCl). Much of the label in these complexes was in molecules other than proteoglycans. Most of the proteoglycans, however, were included on the agarose columns, where they appeared to be constitutionally of low buoyant density. They resisted attempts to separate potential low buoyant density contaminants from the major proteoglycans by direct CsCl density gradient centrifugation or by the fractionation of saline or 8 M urea extracts on diethylaminoethyl-Sephacel. The diethylaminoethyl-Sephacel fractions were either subjected to CsCl density gradient centrifugation or were chromatographed on Sephacryl S-300, in both cases before and after alkaline cleavage, to confirm the presence of typical O-linked glycosaminoglycans. The medium and balanced salt extracts were enriched in chondroitin sulfate and other sulfated macromolecules, possibly highly sulfated oligosaccharides, that resisted digestion by chondroitinase ABC but were electrophoretically less mobile than heparan sulfate. Guanidine HCl or urea extracts of the residues were mixtures of high and low density proteoglycans that were enriched in heparan sulfate.

Asymmetric H-D exchange reactions of fluorinated aromatic ketones

KAUST Repository

Zhao, Yujun

2012-01-01

Chiral bicyclic guanidine catalyzes the asymmetric H-D exchange reactions. Up to 30% ee was achieved. DFT calculations were employed to elucidate and explain the origin of the reaction\\'s stereoselectivity. © 2012 The Royal Society of Chemistry.

QSAR Study of Sucrose and Guanidine Derivatives

African Journals Online (AJOL)

NICO

CAChe Pro software by using eight descriptors,viz.electron affinity, ionization potential, electrophilicity index, total ... development of the AH-B theory of sweetness proposed by .... form of the solution to the quantum mechanical equation as.

Chemsearch Journal Volume 4 Number 1, June, 2013

African Journals Online (AJOL)

Magashi

2013-06-01

Jun 1, 2013 ... The Chemical Fixation of Carbon Dioxide by Tetramethylguanidine and ... for the reaction between CO2 and the guanidine bases at normal temperature and pressure, i.e Ca. 30 °C and 1 ..... Engineering Data, 51(2), 645-647.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Concanavalin A (ConA) is a plant lectin having industrial and biological applications. Concanavalin A changes conformation upon exposure to different stress conditions, like exposure to sodium dodecyl sulphate, guanidine hydrochloride, varying hydronium ion potential, etc. The conformational changes were studied using ...

A potential method using Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2}, (Et{sub 3}Si){sub 2}Te and anhydrous hydrazine for germanium tellurides

Energy Technology Data Exchange (ETDEWEB)

Du, Liyong; Du, Shulei; Ding, Yuqiang [School of Chemical and Material Engineering, Jiangnan University, Wuxi (China)

2017-12-29

A germanium(II)-guanidine derivative of formula Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2} (1) was synthesized and characterized by {sup 1}H NMR, {sup 13}C NMR, elemental analysis, and X-ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et{sub 3}Si){sub 2}Te. Solution reaction of compound 1, (Et{sub 3}Si){sub 2}Te, and anhydrous hydrazine was investigated to pre-identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Shallu. Articles written in Journal of Chemical Sciences. Volume 126 Issue 6 November 2014 pp 1869-1874 Regular Articles. First total synthesis of a guanidine alkaloid Nitensidine D using immobilized ionic liquid, microwaves and formamidinesulfinic acid · Shallu M L ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Thiophene-substituted chalcones were cyclised with guanidine in the presence of potassium hydroxide to get 4-substituted-6-thiophenopyrimidines 2a-e which were then refluxed with acetylacetone to obtain pyrimidopyrimidines 3a-e. Compounds 2a-e were also refluxed with ethylacetoacetate to afford ...

Modified melanocortin tetrapeptide Ac-His-dPhe-Arg-Trp-NH at the arginine side chain with ureas and thioureas.

Science.gov (United States)

Joseph, C G; Sorensen, N B; Wood, M S; Xiang, Z; Moore, M C; Haskell-Luevano, C

2005-11-01

The Ac-His-dPhe-Arg-Trp-NH2 tetrapeptide is a nonselective melanocortin agonist and replacement of Arg in the tetrapeptide with acidic, basic or neutral amino acids results in reduced potency at the melanocortin receptor (MCR) isoforms (MC1R and MC3-5R). To determine the importance of the positive charge and the guanidine moiety for melanocortin activity, a series of urea- and thiourea-substituted tetrapeptides were designed. Replacement of Arg with Lys or ornithine reduced agonist activity at the mouse mMC1 and mMC3-5 receptors, thus supporting the hypothesis that the guanidine moiety is important for receptor potency, particularly at the MC3-5 receptors. The Arg side chain-modified tetrapeptides examined in this study include substituted phenyl, naphthyl, and aliphatic urea and thiourea residues using a Lys side-chain template. These ligands elicit full-agonist pharmacology at the mouse MCRs examined in this study.

Comparison of parasite loads in serum and blood samples from patients in acute and chronic phases of Chagas disease.

Science.gov (United States)

Hernández, Carolina; Teherán, Aníbal; Flórez, Carolina; Ramírez, Juan David

2018-04-17

Molecular methods have been developed for the detection and quantification of Trypanosoma cruzi DNA in blood samples from patients with Chagas disease. However, aspects of sample processing necessary for quantitative real-time PCR (qPCR), such as the addition of guanidine hydrochloride to whole blood samples, may limit timely access to molecular diagnosis. We analysed 169 samples from serum and guanidine-EDTA blood (GEB) obtained from patients in acute and chronic phases of Chagas disease. We applied qPCR targeted to the satellite DNA region. Finally, we compared the parasite loads and cycle of threshold values of the qPCR. The results confirmed the usefulness of serum samples for the detection and quantification of parasite DNA in patients with Chagas disease, especially in the acute phase. However, the parasite loads detected in serum samples from patients in the chronic phase were lower than those detected in GEB samples. The epidemiological implications of the findings are herein discussed.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

An efficient first total synthesis of a naturally occurring guanidine alkaloid, Nitensidine D isolated from ethanol extract of Pterogyne nitens has been described. Geraniol has been used as the starting material. N-alkylation of phthalimide has been achieved using immobilized ionic liquid and formamidinesulfinic acid acts as ...

Anti-hepatitis B viral activity of Phyllanthus niruri L (Phyllanthaceae ...

African Journals Online (AJOL)

Yong Li, Xin Li, Jia-Kun Wang, Yan Kuang and Ming-Xiu Qi*. Centers for Disease .... sarkosyl, 7 % 2-mercaptoethanol, 4 M guanidine ..... AK, Gane E, Hou JL, Jafri W, Jia J, Kim JH, Lai CL, Lee. HC, Lim SG, Liu CJ ... Shin MS, Kang EH, Lee YI.

Mutation induced enhanced biosynthesis of lipase | Bapiraju ...

African Journals Online (AJOL)

The purpose of the present investigation is to enhance production of biomedically important enzyme lipase by subjecting the indigenous lipase producing strain Rhizopus sp. BTS-24 to improvement by natural selection and random mutagenesis (UV and N-methyl-N'-nitro-N-nitroso guanidine, NTG). The isolation of mutants ...

Provisional Peer-Reviewed Toxicity Values for Guanidine Nitrate

Science.gov (United States)

Provisional Peer-Reviewed Toxicity Values (PPRTV) assessments are developed for use by the Agency’s Office of Land and Emergency Management (OLEM) to support informed decisions in the Superfund program and at hazardous waste sites when a values is not available in the Integrated ...

Provisional Peer-Reviewed Toxicity Values for Guanidine Chloride

Science.gov (United States)

Provisional Peer-Reviewed Toxicity Values (PPRTV) assessments are developed for use by the Agency’s Office of Land and Emergency Management (OLEM) to support informed decisions in the Superfund program and at hazardous waste sites when a values is not available in the Integrated ...

Synthesis and conformational features of sym ,',"-triarylguanidines

Indian Academy of Sciences (India)

A one pot reaction involving sym ,'-diarylthiourea and the respective arylamine in the presence of aq. KOH in nitrobenzene at ≥ 105°C afforded sym ,',"-triarylguanidine in fair to good yield and the products have been characterized. Sym ,',"-tri(4-tolyl)guanidine possesses (7) anti-anti conformation, sym ,' ...

Multiple mechanisms of phase variation of PorA in Neisseria meningitidis

NARCIS (Netherlands)

van der Ende, A.; Hopman, C. T.; Dankert, J.

2000-01-01

Previously, we reported that PorA expression in Neisseria meningitidis is modulated by variation in the length of the homopolymeric tract of guanidine residues between the -35 and -10 regions of the promoter or by deletion of porA. To reveal additional mechanisms of variation in PorA expression, the

Effects of Kangshen Oral Liquid on Gentamicin-induced Acute ...

African Journals Online (AJOL)

1Department of Heart-Kidney Internal Medicine, 2Department of Vasculocardiology, 3Department of ... Results: After treatment with KSOL (20, 10, or 5 mL/kg), the RI, activity of NAG and levels of UP, SCr, .... Acetic acid was obtained .... had extreme edema, which resulted in stenosis .... Protective role of amino guanidine on.

Susceptibilities of enterovirus D68, enterovirus 71, and rhinovirus 87 strains to various antiviral compounds.

Science.gov (United States)

Smee, Donald F; Evans, W Joseph; Nicolaou, K C; Tarbet, E Bart; Day, Craig W

2016-07-01

Compounds were evaluated for antiviral activity in rhabdomyosarcoma (RD) cells against a recent 2014 clinical isolate of enterovirus D68 (EV-D68), a 1962 strain of EV-68D, rhinovirus 87 (RV-87, serologically the same as EV-D68), and enterovirus 71 (EV-71). Test substances included known-active antipicornavirus agents (enviroxime, guanidine HCl, pirodavir, pleconaril, and rupintrivir), nucleobase/nucleoside analogs (3-deazaguanine and ribavirin), and three novel epidithiodiketopiperazines (KCN-2,2'-epi-19, KCN-19, and KCN-21). Of these, rupintrivir was the most potent, with 50% inhibition of viral cytopathic effect (EC50) and 90% inhibition (EC90) of virus yield at 0.0022-0.0053 μM against EV-D68. Enviroxime, pleconaril and the KCN compounds showed efficacy at 0.01-0.3 μM; 3-deazaguanine and pirodavir inhibited EV-D68 at 7-13 μM, and guanidine HCl and ribavirin were inhibitory at 80-135 μM. Pirodavir was active against EV-71 (EC50 of 0.78 μM) but not against RV-87 or EV-D68, and all other compounds were less effective against EV-71 than against RV-87 and EV-D68. The most promising compound inhibiting both virus infections at low concentrations was rupintrivir. Antiviral activity was confirmed for the ten compounds in virus yield reduction (VYR) assays in RD cells, and for enviroxime, guanidine HCl, and pirodavir by cytopathic effect (CPE) assays in A549, HeLa-Ohio-1, and RD cells. These studies may serve as a basis for further pre-clinical discovery of anti-enterovirus inhibitors. Furthermore, the antiviral profiles and growth characteristics observed herein support the assertion that EV-D68 should be classified together with RV-87. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis of per-6-guanidinylated cyclodextrins

Czech Academy of Sciences Publication Activity Database

Kraus, Tomáš; Buděšínský, Miloš; Závada, Jiří

2006-01-01

Roč. 47, č. 5 (2006), s. 679-681 ISSN 0040-4039 R&D Projects: GA ČR(CZ) GA203/03/0087; GA ČR(CZ) GP203/01/D082 Institutional research plan: CEZ:AV0Z40550506 Keywords : cyclodextrins * guanidine Subject RIV: CC - Organic Chemistry Impact factor: 2.509, year: 2006

Preparation and characterization of soy protein films with a durable water resistance-adjustable and antimicrobial surface.

Science.gov (United States)

Li, Shuzhao; Donner, Elizabeth; Xiao, Huining; Thompson, Michael; Zhang, Yachuan; Rempel, Curtis; Liu, Qiang

2016-12-01

A water resistant surface was first obtained by immobilizing hydrophobic copolymers, poly (styrene-co-glycidyl methacrylate) (PSG), with functional groups on soy protein isolate (SPI) films. XPS and AFM results showed that PSG copolymers were immobilized on the film by chemical bonding, and formed a rough surface with some bumps because of the segregation of two different phases on PSG copolymers. Water resistance of the modified films could be adjusted dramatically by further immobilizing different amounts of guanidine-based antimicrobial polymers, poly (hexamethylene guanidine hydrochloride) (PHMG) on the resulting hydrophobic surface. The introduction of hydrophilic PHMG on the resulting surface generated many micropores, which potentially increased the water uptake of the modified films. Furthermore, the modified SPI films showed higher thermostability compared to native SPI film and broad-spectrum antimicrobial activity by contact killing, attributed to the presence of PHMG on the surface. The modified SPI film with a multi-functional surface showed potential for applications in the packaging and medical fields. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Acid-base synergistic flame retardant wood pulp paper with high thermal stability.

Science.gov (United States)

Wang, Ning; Liu, Yuansen; Xu, Changan; Liu, Yuan; Wang, Qi

2017-12-15

Acid-catalytic degradation caused by acid source flame retardants is the main reason for a decline in thermal stability of flame-retarded lignocellulosic materials. In the present research, a guanidine phosphate (GP)/borax (BX) flame retardant system based on acid-base synergistic interaction was designed and used in wood pulp paper (WPP) to solve this problem. Results showed that the treated WPP obtained good flame retardancy with a limiting oxygen index (LOI) value of 35.7%. As a basic flame retardant, borax could chemically combine with the acids released by guanidine phosphate, thus decreasing the acidity of the system in the initial heating stage. In this way, acid-catalytic degradation is greatly retarded on the lignocelluloses to improve thermal stability (the temperature of maximum degradation peak from 286°C to 314°C). Meanwhile, borax was also advantageous to form a denser and firmer condensed phase through reinforcement of the acid-base reaction product, borophosphates, allowing it to provide a protective barrier with higher quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

The distribution of alternative agents for targeted radiotherapy within human neuroblastoma spheroids

International Nuclear Information System (INIS)

Mairs, R.J.; Gaze, M.N.; Murray, T.; Reid, R.; McSharry, C.; Babich, J.W.

1991-01-01

This study aims to select the radiopharmaceutical vehicle for targeted radiotherapy of neuroblastoma which is most likely to penetrate readily the centre of micrometastases in vivo. The human neuroblastoma cell line NB1-G, grown as multicellular spheroids provided an in vitro model for micrometastases. The radiopharmaceuticals studied were the catecholamine analogue metaiodobenzyl guanidine (mIBG), a specific neuroectodermal monoclonal antibody (UJ13A) and β nerve growth factor (βNGF). Following incubation of each drug with neuroblastoma spheroids, autoradiographs of frozen sections were prepared to demonstrate their relative distributions. mIBG and βNGF were found to penetrate the centre of spheroids readily although the concentration of mIBG greatly exceeded that of βNGF. In contrast, UJ13A was only bound peripherally. We conclude that mIBG is the best available vehicle for targeted radiotherapy of neuroblastoma cells with active uptake mechanisms for catecholimines. It is suggested that radionuclides with a shorter range of emissions than 131 I may be conjugated to benzyl guanidine to constitute more effective targeting agents with potentially less toxicity to adjacent normal tissues. (author)

Microwave-Assisted Synthesis and Biological Evaluation of Dihydropyrimidinone Derivatives as Anti-Inflammatory, Antibacterial, and Antifungal Agents

Directory of Open Access Journals (Sweden)

Anjna Bhatewara

2013-01-01

Full Text Available A simple protocol for the efficient preparation of aryl and heteroaryl substituted dihydropyrimidinone has been achieved via initial Knoevenagel, subsequent addition, and final cyclization of aldehyde, ethylcyanoacetate, and guanidine nitrate in the presence of piperidine as a catalyst in solvent-free under microwave irradiation. The synthesized compounds showed a good anti-inflammatory, antibacterial, and antifungal activity.

Method for reducing heat loss during injection of hot water into an oil stratum

Energy Technology Data Exchange (ETDEWEB)

Evgenev, A E; Kalashnikov, V N; Raiskii, Yu D

1968-07-01

A method is described for reduction of heat loss during the injection of hot water into an oil stratum. During the transportation of the hot water to the face of the bore holes, it has high-molecular polymers added to it. The high-molecular polymer may be guanidine or polyoxyethylene in the quantity of 0.01 to 0.03% by wt.

Primary Eye Irritation of Guanidine Nitrate in Male Rabbits.

Science.gov (United States)

1986-01-01

4 IRIS Normal ............................................................... 0 Markedly deepened rugae , congestion, swelling...the rugae or a slight hyperemia of the circumcorneal blood vessels); an obvious swelling in the conjunctiva (excluding the cornea and iris) with partial

Guanidination of notexin alters its membrane-damaging activity in ...

Indian Academy of Sciences (India)

MADHU

is a basic protein with 119 amino acids and 7 disulphide ... 2Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan ..... secretory phospholipase A2 from studies on native and chimeric proteins ...

Role of quaternary structure in muscle creatine kinase stability: tryptophan 210 is important for dimer cohesion.

Science.gov (United States)

Perraut, C; Clottes, E; Leydier, C; Vial, C; Marcillat, O

1998-07-01

A mutant of the dimeric rabbit muscle creatine kinase (MM-CK) in which tryptophan 210 was replaced has been studied to assess the role of this residue in dimer cohesion and the importance of the dimeric state for the native enzyme stability. Wild-type protein equilibrium unfolding induced by guanidine hydrochloride occurs through intermediate states with formation of a molten globule and a premolten globule. Unlike the wild-type enzyme, the mutant inactivates at lower denaturant concentration and the loss of enzymatic activity is accompanied by the dissociation of the dimer into two apparently compact monomers. However, the Stokes radius of the monomer increases with denaturant concentration as determined by size exclusion chromatography, indicating that, upon monomerization, the protein structure is destabilized. Binding of 8-anilinonaphthalene-1-sulfonate shows that the dissociated monomer exposes hydrophobic patches at its surface, suggesting that it could be a molten globule. At higher denaturant concentrations, both wild-type and mutant follow similar denaturation pathways with formation of a premolten globule around 1.5-M guanidine, indicating that tryptophan 210 does not contribute to a large extent to the monomer conformational stability, which may be ensured in the dimeric state through quaternary interactions.

The structural basis of urea-induced protein unfolding in β-catenin

Science.gov (United States)

Wang, Chao; Chen, Zhongzhou; Hong, Xia; Ning, Fangkun; Liu, Haolin; Zang, Jianye; Yan, Xiaoxue; Kemp, Jennifer; Musselman, Catherine A.; Kutateladze, Tatinna G.; Zhao, Rui; Jiang, Chengyu; Zhang, Gongyi

2014-01-01

Although urea and guanidine hydrochloride are commonly used to denature proteins, the molecular underpinnings of this process have remained unclear for a century. To address this question, crystal structures of β-catenin were determined at various urea concentrations. These structures contained at least 105 unique positions that were occupied by urea molecules, each of which interacted with the protein primarily via hydrogen bonds. Hydrogen-bond competition experiments showed that the denaturing effects of urea were neutralized when polyethylene glycol was added to the solution. These data suggest that urea primarily causes proteins to unfold by competing and disrupting hydrogen bonds in proteins. Moreover, circular-dichroism spectra and nuclear magnetic resonance (NMR) analysis revealed that a similar mechanism caused protein denaturation in the absence of urea at pH levels greater than 12. Taken together, the results led to the conclusion that the disruption of hydrogen bonds is a general mechanism of unfolding induced by urea, high pH and potentially other denaturing agents such as guanidine hydrochloride. Traditionally, the disruption of hydrophobic inter­actions instead of hydrogen bonds has been thought to be the most important cause of protein denaturation. PMID:25372676

Purification of a large molecular weight transglutaminase substrate from liver plasma membranes

International Nuclear Information System (INIS)

Slife, C.W.; Morris, G.S.; Tyrrell, D.J.

1986-01-01

Transglutaminases are enzymes which catalyze the covalent crosslinking of proteins by forming epsilon(γ-glutamyl)lysine isopeptide linkages. In earlier studies, the authors reported that a large molecular weight protein aggregate in rat liver plasma membranes served as a substrate for a plasma membrane-associated transglutaminase. The enzyme specifically incorporated a lysine analog, [ 3 H]putrescine, into a protein complex which remained at the top of an acrylamide gel upon electrophoresis in SDS and reducing agents. The complex has now been isolated by extracting the plasma membranes with detergent (octylglucoside) resuspending the detergent insoluble residues in 6 M guanidine HCl and chromatographing the residue on a 4% agarose column in 6 M guanidine HCl. Most of the radioactivity is found in the void volume fractions from the column. SDS polyacrylamide gel electrophoresis shows that these fractions contain mostly proteins that do not enter the acrylamide gel. Since this purification procedure is essentially the same as that used to isolate a rat hepatocyte adhesion factor from rat liver plasma membranes it is possible that the large molecular weight transglutaminase substrate and the adhesion factor are contained in the same protein aggregate

[Synthesis and physico-chemical characterisation of some new derivatives of rutoside and clofibric acid].

Science.gov (United States)

Lupaşcu, D; Profire, Lenuţa; Dănilă, Gh

2006-01-01

Fibrates are drugs with efficacy in reducing blood cholesterol levels and especially, triglyceride plasma levels. Unfortunately, fibrates have a poor water-solubility and showed some adverse reactions at long treatment. The objective of this study was to obtain some new clofibric acid derivatives with rutin; some of these compounds contain a guanidine moiety, known as effective at cardiovascular level. All the compounds are soluble in water.

Design, synthesis and evaluation of 4,7-diamino-1,10-phenanthroline G-quadruplex ligands

DEFF Research Database (Denmark)

Nielsen, Mads Corvinius; Borch, Jonas; Ulven, Trond

2009-01-01

the central ionic column. Introduction of positively charged side chains results in compounds with appreciable G-quadruplex stabilizing properties and high aqueous solubility, with the longer side chains giving more potent compounds. Ligands carrying guanidine side chains in general show higher quadruplex...... stabilizing activity and distinctly slower kinetic properties than their amino and dimethylamino analogues, possibly due to specific hydrogen bond interactions with the G-quadruplex loops....

A review of Explosives Used in Explosive Excavation Research Laboratory Projects Since 1969

Science.gov (United States)

1974-12-01

Boron compounds Potassium dichramat« Antimony compounds Bismuth compounds P«riodat«s Litharge Guar gum (polysaccSarid«) Storch Acrylomid... gum , and gelled with a cross- linking agent. The i-arliest slurries used Government surplus TNT as a fuel-sensitizer, but the majority o...Nonexplosive TNT PETN RDX Rentalite Composition B Guanidine nitrate Smokeless powder Nitres*: ch Alky’amine nitrates Nit.omannite Aluminum Sugar

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

International Nuclear Information System (INIS)

Pilli, Ronaldo A.; Rodrigues Junior, Manoel Trindade

2009-01-01

A concise and efficient total synthesis of (+)- and (-)-trypargine (6 steps and 38% overall yield), a 1-substituted β-carboline guanidine alkaloid isolated from the skin of the African frog K. senegalensis, was developed based on the construction of the b-carboline moiety via Bischler-Napieralski reaction and the enantioselective reduction of the dihydro-β-carboline intermediate via an asymmetric transfer hydrogenation reaction using Noyori's protocol. (author)

Explosive Performance Modification by Cosolidification of Ammonium Nitrate with Fuels

Science.gov (United States)

1976-10-01

explosives, by calibrated codes and formulas (Rif 1-4). It has been recognized that departure from the instantan- eity approximation may be significant...velocity nor density changed much. No other explanation of the synergism se.-. as tenable as intermolecular reaction behind the shock front yielding...delivery problems with UDMH ). Among potentially interesting materials which were deferred or to receive less attention were nitro- guanidine nitrate

The First Total Synthesis of Dragmacidin D

OpenAIRE

Garg, Neil K.; Sarpong, Richmond; Stoltz, Brian M.

2002-01-01

The first total synthesis of the biologically significant bis-indole alkaloid dragmacidin D (5) has been achieved. Thermal and electronic modulation provides the key for a series of palladium-catalyzed Suzuki cross-coupling reactions that furnished the core structure of the complex guanidine- and aminoimidazole-containing dragmacidins. Following this crucial sequence, a succession of meticulously controlled final events was developed leading to the completion of the natural product.

Transition-state characterization: a new approach combining inhibitor analogues and variation in enzyme structure.

Science.gov (United States)

Phillips, M A; Kaplan, A P; Rutter, W J; Bartlett, P A

1992-02-04

A new strategy of potentially broad application for probing transition-state (TS) analogy in enzymatic systems is described in this paper. The degree to which a series of phosphonate inhibitors act as TS analogues of rat carboxypeptidase A1 has been determined for the wild-type enzyme, for the R127K, R127M, and R127A mutants, and for the R127A mutant in the presence of 0.5 M guanidine hydrochloride. The impact that the mutations have on the inverse second-order rate constants (Km/kcat) for substrate hydrolysis is mirrored by the effect on the inhibition constants (Ki) for the corresponding phosphonate inhibitors. These results demonstrate that the phosphonate moiety mimics some of the electronic as well as the geometric characteristics of the TS. A similar but distinctly separate correlation is observed for tripeptide analogues in comparison to analogues of the dipeptide Cbz-Gly-Phe, reflecting an anomalous mode of binding for the latter system. The selective rate increases and corresponding enhancement in inhibitor binding observed on addition of 0.5 M guanidine hydrochloride to the R127A mutant indicate that the exogenous cation can assume the role played by Arg-127 in stabilizing the TS and in providing substrate selectivity at the P2 position.

Hybrid process for nitrogen oxides reduction

Energy Technology Data Exchange (ETDEWEB)

Epperly, W.R.; Sprague, B.N.

1991-09-10

This patent describes a process for reducing the nitrogen oxide concentration in the effluent from the combustion of a carbonaceous fuel. It comprises introducing into the effluent a first treatment agent comprising a nitrogenous composition selected from the group consisting of urea, ammonia, hexamethylenetetramine, ammonium salts of organic acids, 5- or 6-membered heterocyclic hydrocarbons having at least one cyclic nitrogen, hydroxy amino hydrocarbons, NH{sub 4}-lignosulfonate, fur-furylamine, tetrahydrofurylamine, hexamethylenediamine, barbituric acid, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, biuret, 1.1{prime}-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, calcium cyanamide, and mixtures thereof under conditions effective to reduce the nitrogen oxides concentration and ensure the presence of ammonia in the effluent; introducing into the effluent a second treatment agent comprising an oxygenated hydrocarbon at an effluent temperature of about 500{degrees} F. to about 1600{degrees} F. under conditions effective to oxidize nitric oxide in the effluent to nitrogen dioxide and ensure the presence of ammonia at a weight ratio of ammonia to nitrogen dioxide of about 1:5 to about 5:1; and contacting the effluent with an aqueous scrubbing solution having a pH of 12 or lower under conditions effective to cause nitrogen dioxide to be absorbed therein.

Adsorption of CO2 on amine-functionalised MCM-41: experimental and theoretical studies.

Science.gov (United States)

dos Santos, Thiago Custódio; Bourrelly, Sandrine; Llewellyn, Philip L; Carneiro, José Walkimar de M; Ronconi, Célia Machado

2015-04-28

Adsorption of CO2 on MCM-41 functionalised with [3-(2-aminoethylamino)propyl]trimethoxysilane (MCM-41-N2), N(1)-(3-trimethoxysilylpropyl)diethylenetriamine (MCM-41-N3), 4-aminopyridine (MCM-41-aminopyridine), 4-(methylamino)pyridine (MCM-41-methylaminopyridine) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (MCM-41-guanidine) was investigated. The amine-functionalised materials were characterised by (29)Si and (13)C solid-state nuclear magnetic resonance, N2 adsorption/desorption isotherms, X-ray diffraction and transmission electron microscopy. CO2 adsorption at 1.0 bar and 30 °C showed that the amount of CO2 (nads/mmol g(-1)) adsorbed on MCM-41-N2 and MCM-41-N3 is approximately twice the amount adsorbed on MCM-41. For MCM-41-aminopyridine, MCM-41-methylaminopyridine and MCM-41-guanidine, the CO2 adsorption capacity was smaller than that of MCM-41 at the same conditions. The proton affinity (computed with wB97x-D/6-311++G(d,p)) of the secondary amino groups is higher than that of the primary amino groups; however, the relative stabilities of the primary and secondary carbamates are similar. The differential heat of adsorption decreases as the number of secondary amino groups increases.

Guanicid and PHMG Toxicity Tests on Aquatic Organisms

OpenAIRE

Eva Poštulková; Radovan Kopp

2016-01-01

The emergence and development of new algicidal products is caused by the ever increasing popularity of garden ponds as well as the use of these products in the fisheries sector, especially for disposal of cyanobacteria and algae. Most frequent means of combating cyanobacteria and algae are applications of algicidal substances. Newly developed algaecides include Guanicid and polyhexamethylene guanidine hydrochloride (PHMG). The aim of the study was to identify toxic effects of Guanicid and PHM...

Synthesis and properties of 2-guanidinopurines

Czech Academy of Sciences Publication Activity Database

Česnek, Michal; Masojídková, Milena; Holý, Antonín; Šolínová, Veronika; Koval, Dušan; Kašička, Václav

2006-01-01

Roč. 71, č. 9 (2006), s. 1303-1319 ISSN 0010-0765 R&D Projects: GA MŠk(CZ) 1M0508; GA AV ČR(CZ) 1QS400550501; GA ČR(CZ) GA203/05/2539 Grant - others:René Descartes Prize(XE) HPAW-2002-100096 Institutional research plan: CEZ:AV0Z40550506 Keywords : purines * nucleosides * guanidines * basicity Subject RIV: CC - Organic Chemistry Impact factor: 0.881, year: 2006

Synthesis of Some Novel Pyrimidine Derivatives and Investigation of their Electrochemical Behavior

International Nuclear Information System (INIS)

Akbas, Esvet; Gumus, Selcuk; Sumer, Mehmet Rauf; Akyaz, Inci; Levent, Abdulkadir

2010-01-01

2-Iminopyrimidines (1a-e) and 2-thioxopyrimidine (2) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β-diketone, arylaldehyde, and guanidine (for 1a-e) or thiourea (for 2). The electrochemical properties of the novel systems were investigated by CV and DPV. Moreover, B3LYP/6-31G(d,p) method was applied to the present structures in order to gather some structural and physicochemical data

Annual Progress Report, October 1, 1982 - September 15, 1983 on Contract N00014-79-C-0126,

Science.gov (United States)

1983-09-15

bulk of bound Na+ (i.e., 77/) ar displaced by 300 rrM guar =dre. However, at 100 mrM concentration, the most effective displacement was not guanidine...polyvinylmethylether (PVME), and a counter and expressed as a ratio to thenumber of native gums , polysaccharides, etc.A labelled Na" concentration in...precipitation and deterioration of the organic components in the GIB medium. The GIB medium was obtained in sterile dry powder form from Grand Island

Synthesis and antibacterial and antifungal studies of novel nitrogen containing heterocycles from 5-Ethylpyridin-2-ethanol

OpenAIRE

Patel N; Patel H

2010-01-01

A novel series of chalcones, pyrimidines and imidazolinone is described; chalcones (4a-o) were prepared from the lead molecule 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde. Pyrimidine (5a-o) derivatives were prepared from the reaction of chalcones and guanidine nitrate in alkali media. Imidazolinones (6a-o) were synthesized from reaction of pyrimidine and oxazolone derivatives (prepared by Erlenmeyer azlactone synthesis). The structures of the synthesized compounds were assigned on the basis...

Increased RNAi Efficacy in Spodoptera exigua via the Formulation of dsRNA With Guanylated Polymers

Directory of Open Access Journals (Sweden)

Olivier Christiaens

2018-04-01

Full Text Available Lepidoptera comprise some of the most devastating herbivorous pest insects worldwide. One of the most promising novel pest control strategies is exploiting the RNA interference (RNAi mechanism to target essential genes for knockdown and incite toxic effects in the target species without harming other organisms in the ecosystem. However, many insects are refractory to oral RNAi, often due to rapid degradation of ingested dsRNA in their digestive system. This is the case for many lepidopteran insects, including the beet armyworm Spodoptera exigua, which is characterized by a very alkaline gut environment (pH > 9.0 and a strong intestinal nucleolytic activity. In this research, guanidine-containing polymers were developed to protect dsRNA against nucleolytic degradation, specifically in high pH environments. First, their ability to protect dsRNA against nucleolytic degradation in gut juice of the beet armyworm S. exigua was investigated ex vivo. Polymers with high guanidine content provided a strong protection against nucleolytic degradation at pH 11, protecting the dsRNA for up to 30 h. Next, cellular uptake of the dsRNA and the polyplexes in lepidopteran CF203 midgut cells was investigated by confocal microscopy, showing that the polymer also enhanced cellular uptake of the dsRNA. Finally, in vivo feeding RNAi bioassays demonstrated that using these guanidine-containing polymer nanoparticles led to an increased RNAi efficiency in S. exigua. Targeting the essential gene chitin synthase B, we observed that the mortality increased to 53% in the polymer-protected dsRNA treatment compared to only 16% with the naked dsRNA and found that polymer-protected dsRNA completely halted the development of the caterpillars. These results show that using guanylated polymers as a formulation strategy can prevent degradation of dsRNA in the alkaline and strongly nucleolytic gut of lepidopteran insects. Furthermore, the polymer also enhances cellular uptake in

Improving Gold Recovery from Artificial Preg-Robbing Ore by Pre-treatment using Blinding Agent and Resin-in-Leach

OpenAIRE

Mohammad Zaki Mubarok; Prasetyo Sandha Irianto

2016-01-01

In the present paper, the effectiveness of the use of blinding agents, ionic exchanger resins and the combination of them in improving gold extraction from simulated preg-robbing ore is discussed. The blinding agents used were kerosene, diesel oil and pine oil, while the ion exchange resins used were Lewatit Monoplus MP 800, Lewatit AF 5 and guanidine. Preg-robbing conditions were simulated by blending fine activated carbon with ore sample. The investigation results show that the presence of ...

Identification of Bacillus anthracis by Using Monoclonal Antibody to Cell Wall Galactose-N-Acetylglucosamine Polysaccharide

Science.gov (United States)

1990-02-01

Bacillus circulans ATCC 4513 b - - NR NT NT NT NT Bacillus coagulans ATCC 7050 b - - NR NT NT NT NT Bacillus eugilitis B-61 f - - NR NT NT NT NT...American Society for Microbiology W Identification of Bacillus anthracis by-U-sing Monoclonal Antibody CC to Cell Wall Galactose-N-Acetylglucosamine...Received 22 June 1989/Accepted 31 October 1989 ’ Guanidine extracts of crude Bacillus anthracis cell wall were used to vaccinate BALB/c mice and to

Properties of the catalase molecule obtained from acatalasemic and hypocatalasemic mice Part I. Effects of denaturants on the catalase activity in the mouse liver

OpenAIRE

佐藤, 征紀

1985-01-01

Homogenates of mouse liver with isotonic sucrose solution were separated by the cell fractionation with repeating centrifugation. The supernatants were used for the inhibition test with the reagents such as 3,5 diiodosalicylic acid lithium salt (LIS), guanidine and azide, heat, acid and alkali. After various treatments, the remaining catalase activities were measured and showed as a relative enzyme activity. Stability of catalase in liver supernatants was compared normal (C3H/C(as)C(as)) and ...

Drug: D06689 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available D06689 Crude ... Drug Phellodendron bark (JP17); Powdered phellodendron bark (JP17); Phello...dendron bark (TN) Berberine [CPD:C00757], Palmatine [CPD:C05315], Magnoflorine [CPD:C09581], Phello...esterol [CPD:C01789], Guanidine [CPD:C17349], Candicine [CPD:C10575], Menisperine, 7-Dehydrostigmasterol ... Phello...dendron amurense [TAX:68554], Phellodendron chinense [TAX:354508] ... Same as: E00063 Therapeutic catego...ry: 5100 ... Rutaceae (rue family) Phellodendron bark Major component: Berberine [CPD:C00757] ... PubChem: 47208340 ...

Design, synthesis and development of novel indolocarbazole derivatives as potential anti-cancer agents

OpenAIRE

Pierce, Laurence Thomas

2011-01-01

This thesis describes work carried out on the design of new routes to a range of bisindolylmaleimide and indolo[2,3-a]carbazole analogs, and investigation of their potential as successful anti-cancer agents. Following initial investigation of classical routes to indolo[2,3-a]pyrrolo[3,4-c]carbazole aglycons, a new strategy employing base-mediated condensation of thiourea and guanidine with a bisindolyl β-ketoester intermediate afforded novel 5,6-bisindolylpyrimidin-4(3H)-ones in moderat...

Partially folded intermediates during trypsinogen denaturation

Directory of Open Access Journals (Sweden)

Martins N.F.

1999-01-01

Full Text Available The equilibrium unfolding of bovine trypsinogen was studied by circular dichroism, differential spectra and size exclusion HPLC. The change in free energy of denaturation was = 6.99 ± 1.40 kcal/mol for guanidine hydrochloride and = 6.37 ± 0.57 kcal/mol for urea. Satisfactory fits of equilibrium unfolding transitions required a three-state model involving an intermediate in addition to the native and unfolded forms. Size exclusion HPLC allowed the detection of an intermediate population of trypsinogen whose Stokes radii varied from 24.1 ± 0.4 Å to 26.0 ± 0.3 Å for 1.5 M and 2.5 M guanidine hydrochloride, respectively. During urea denaturation, the range of Stokes radii varied from 23.9 ± 0.3 Å to 25.7 ± 0.6 Å for 4.0 M and 6.0 M urea, respectively. Maximal intrinsic fluorescence was observed at about 3.8 M urea with 8-aniline-1-naphthalene sulfonate (ANS binding. These experimental data indicate that the unfolding of bovine trypsinogen is not a simple transition and suggest that the equilibrium intermediate population comprises one intermediate that may be characterized as a molten globule. To obtain further insight by studying intermediates representing different stages of unfolding, we hope to gain a better understanding of the complex interrelations between protein conformation and energetics.

Inhibition of host cell protein synthesis by UV-inactivated poliovirus

International Nuclear Information System (INIS)

Helentjaris, T.; Ehrenfeld, E.

1977-01-01

The ability of poliovirus that was irradiated with UV light at energies up to 2,160 ergs/mm 2 to subsequently inhibit host cell protein synthesis was measured. The inactivation of the host cell shutoff function followed one-hit kinetics. Increasing irradiation did not affect the rate of inhibition until the multiplicity of infection after irradiation was reduced to approximately 1 PFU/cell. At higher functional multiplicities, the rate was unchanged, but an increasing lag before the onset of inhibition was observed with increasing irradiation. The energy levels required to inactivate virus-induced inhibition of host cell protein synthesis suggest that damage to virus RNA rather than to virus capsid proteins is responsible for the loss of function. When the inactivation of host cell shutoff was compared with the inactivation of other viral functions by UV irradiation, it correlated exactly with the loss of infectivity but not with other viral functions measured. Guanidine treatment, which prevents detectable viral RNA and protein synthesis, completely inhibited host cell shutoff by low multiplicities of unirradiated virus infection but not higher multiplicities. When a high multiplicity of virus was first reduced to a low titer by irradiation, host cell shutoff was still evident in the presence of guanidine. The results demonstrate that the complete inhibition of host cell protein synthesis can be accomplished by one infectious viral genome per cell

Labelling of some organic compounds with radioactive iodine for medical uses

International Nuclear Information System (INIS)

El-tawoosy, M.E.M.

1997-01-01

Among all radioisotopes, radioiodine(i.e. 122 I, 123 I, 125 I. 131 I) is the most available tagging element when considering new radiopharmaceutical compounds intended for nuclear medicine uses for in -Vitro and in - vivo measurements. The aim of this work is to optimize and developed new methods of radioiodination of some organic molecules for use in nuclear medicine as diagnostic agents. Some trials for labelling of meta - iodo benzyl guanidine (MIBG), antipyrine (AP) and 3,5,3- tri - iodothyronine (T 3 ) will be done. In the present study, we will try to get easier, short time, high yield, high specific activity, high radiochemical purity and economic methods for the preparation of the following radiopharmaceutical compounds: 1- (m- 131 I) meat - iodo benzyl guanidine (m- 131 I) MIBG for adrenal medulla and myocardial measurements. 2-(4- 131 I) iodoantipyrine (4- 131 I) IAP for brain measurements. 3-( 131 I) tetra -iodothyronine ( 131 I) T 4 for thyroid gland function studies. The influence of substrate conc., reaction time, different oxidizing agents and catalyst concentrations will be investigated to elucidate the optimum methods suitable for preparation of these compounds. Chromatographic techniques such as paper chromatography, thin layer chromatography (TLC), column chromatography and high pressure liquid chromatography (HPLC) will be used for the identification, quality control, purification and quality assurance of the final product. 4.2 tabs., 4.5 figs., 204 refs

Biomimetic soluble collagen purified from bones.

Science.gov (United States)

Ferreira, Ana Marina; Gentile, Piergiorgio; Sartori, Susanna; Pagliano, Cristina; Cabrele, Chiara; Chiono, Valeria; Ciardelli, Gianluca

2012-11-01

Type I collagen has been extensively exploited as a biomaterial for biomedical applications and drug delivery; however, small molecular alterations occurring during the isolation procedure and its interaction with residual bone extracellular matrix molecules or proteins might affect the overall material biocompatibility and performance. The aim of the current work is to study the potential alterations in collagen properties and organization associated with the absence of proteoglycans, which mimic pathological conditions associated with age-related diseases. A new approach for evaluating the effect of proteoglycans on the properties of isolated type I collagen from the bone matrix is described. Additional treatment with guanidine hydrochloride was introduced to remove residual proteoglycans from the collagen matrix. The properties of the isolated collagen with/without guanidine hydrochloride treatment were investigated and compared with a commercial rabbit collagen as control. We demonstrate that the absence of proteoglycans in the isolated type I collagen affects its thermal properties, the extraction into its native structure, and its ability to hydrate and self-assemble into fibers. The fine control and tuning of all these features, linked to the absence of non-collagenous proteins as proteoglycans, offer the possibility of designing new strategies and biomaterials with advanced biomimetic properties aimed at regenerating bone tissue in the case of fragility and/or defects. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and theoretical studies on nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan (ADNAAF).

Science.gov (United States)

Zheng, Chunmei; Chu, Yuting; Xu, Liwen; Lei, Wu; Wang, Fengyun; Xia, Mingzhu

2017-01-01

Multi-furazan compounds bis[4-nitramino- furazanyl-3-azoxy]azofurazan (ADNAAF) and its derivatives were first synthesized by our research group, and their structures were characterized by IR, 1 H-NMR, 13 C-NMR spectrums, and element analysis. ADNAAF was synthesized by nitration reaction of bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF), and then reacted with ammonium hydroxide, hydrazine hydrate, and guanidine nitrate to obtain three salts marked as salt 1, 2, and 3, respectively. The thermal stabilities of the three salts were supported by the results of DSC analysis, which shows the decomposition temperatures are all above 190 °C. Their densities, enthalpies of formation, and detonation properties were studied by density functional theory (DFT) method. Salt 1 has the best detonation pressure (P), 37.42 GPa, and detonation velocity (D), 8.88 km/s, while salt 2 has the best nitrogen content and heat of detonation (Q), 1.27 kcal mol -1 . The detonation properties of salt 1 is similar to that of 1,3,5-trinitro-1,3,5-triazineane (RDX). It means that the ammonium cation can provide the better D and P than the cation of hydrazine and guanidine. The three cations offer the enthalpies of formations in the order of hydrazinium > guanidinium > ammonium. Graphical Abstract Nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan(ADNAAF).

Chemical modification as a probe of the topography and reactivity of horse-spleen apoferritin

International Nuclear Information System (INIS)

Wetz, K.; Crichton, R.R.; Louvain Univ.

1976-01-01

In apoferritin, but not in ferritin, 1.0 +- 0.1 cysteine residue per subunit can be modified. In ferritin 3.3 +- 0.3 lysine residues and 7.1 +- 0.7 carboxyl groups per subunit can be modified, whilst the corresponding values for apoferritin are 4.4 +- 0.4 lysine residues and 11.0 +- 0.4 carboxyl groups per subunit. Modification of lysine residues with maleic anhydride and of carboxyl groups with glycineamide in apoferritin which has been dissociated and denatured in guanidine hydrochloride leads to the introduction of 9.1 +- 0.5 maleyl groups per subunit and 22.0 +- 0.9 glycineamide residues per subunit. Whereas unmodified apoferritin subunit can be reassociated from guanidine hydrochloride to apoferritin monomer, the ability of maleylated apoferritin to reassociate is impaired. Apoferritin in which all the carboxyl group have been blocked with glycineamide cannot be reassociated to apoferritin and exists in solution as stable subunits. The modification of one cysteine residue per subunit, of 3 or 4 lysine per subunit or of 7 carboxyl groups per subunit has no effect on the catalytic activity of apoferritin. In contrast, the modification of 11 carboxyl groups per subunit completely abolishes the catalytic properties of the protein. We conclude that one or more carboxyl groups are essential for the catalytic activity of horse spleen apoferritin. (orig.) [de

Gas-phase structure and fragmentation pathways of singly protonated peptides with N-terminal arginine.

Science.gov (United States)

Bythell, Benjamin J; Csonka, István P; Suhai, Sándor; Barofsky, Douglas F; Paizs, Béla

2010-11-25

The gas-phase structures and fragmentation pathways of the singly protonated peptide arginylglycylaspartic acid (RGD) are investigated by means of collision-induced-dissociation (CID) and detailed molecular mechanics and density functional theory (DFT) calculations. It is demonstrated that despite the ionizing proton being strongly sequestered at the guanidine group, protonated RGD can easily be fragmented on charge directed fragmentation pathways. This is due to facile mobilization of the C-terminal or aspartic acid COOH protons thereby generating salt-bridge (SB) stabilized structures. These SB intermediates can directly fragment to generate b(2) ions or facilely rearrange to form anhydrides from which both b(2) and b(2)+H(2)O fragments can be formed. The salt-bridge stabilized and anhydride transition structures (TSs) necessary to form b(2) and b(2)+H(2)O are much lower in energy than their traditional charge solvated counterparts. These mechanisms provide compelling evidence of the role of SB and anhydride structures in protonated peptide fragmentation which complements and supports our recent findings for tryptic systems (Bythell, B. J.; Suhai, S.; Somogyi, A.; Paizs, B. J. Am. Chem. Soc. 2009, 131, 14057-14065.). In addition to these findings we also report on the mechanisms for the formation of the b(1) ion, neutral loss (H(2)O, NH(3), guanidine) fragment ions, and the d(3) ion.

An analysis of a humidifier disinfectant case from a toxicological perspective

OpenAIRE

Kwangsik Park

2016-01-01

An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG) shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. Howev...

Chemical constituents of the flowers of Pterogyne nitens (caesalpinioideae); Constituintes quimicos das flores Pterogyne nitens (caesalpinioideae)

Energy Technology Data Exchange (ETDEWEB)

Regasini, Luis Octavio; Fernandes, Daniara Cristina; Castro-Gamboa, Ian; Silva, Dulce Helena Siqueira; Furlan, Maysa; Bolzani, Vanderlan da Silva [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica]. E-mail: bolzaniv@iq.unesp.br; Barreiro, Eliezer Jesus [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Farmacia. Centro de Ciencias da Saude; Cardoso-Lopes, Elaine Monteiro; Young, Maria Claudia Marx; Torres, Luce Brandao [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Fisiologia e Bioquimica de Plantas; Vellosa, Jose Carlos Rebuglio; Oliveira, Olga Maria Mascarenhas de [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica e Tecnologia

2008-07-01

The phytochemical investigation of the flowers of Pterogyne nitens (Caesalpinioideae) resulted in the isolation and identification of nine phenolic derivatives, quercetin 3-O-sophoroside, taxifolin, astilbin, ourateacatechin, caffeic, ferulic, sinapic, chlorogenic and gallic acid, besides two guanidine alkaloids, pterogynine, pterogynidine. This is the first time these compounds have been reported in P. nitens flowers. As this is a monospecific genus, these secondary metabolites may have taxonomical significance. Their structures were assigned on the basis of spectroscopic analyses, including two-dimensional NMR techniques. (author)

Pharmacokinetics of 125-I-labelled meta-iodo-benzyl-guanidine : Preliminary results

International Nuclear Information System (INIS)

Mansouri, A.; Benhidour, A. , Algiers; Algeria)

1993-01-01

The study of some pharmacokinetics providing the mechanism of uptake amd metabolism parameters for the 125-I-mIBG is described. NMRI mice are used for plasma binding study, the animals are killed by decapitation after intravenously (IV) injection of 125-I-mIBG. Wistar rats are used in urinary excretion study. After IV injection, animals are placed in metabolic cages to collect urine. For biodistribution, the rats are killed at different time intervals. The considered organs are removed. The radioactivity of all parameters was performed by gamma counter. The results show that the blood clearance is very high after several hours post injection and very high after 72 hours. Furthermore, we note a rapid excretion of radioactivity 24 hours post injection. However, we observe that 72 hours after injection, the radioactivity per gram of different organs was normalized according to the adrenal glands. Also, we note, that the adrenal glands may be the only target organs 48 hours post injection. These results confirm that 125-I-mIBG a high affinity for the adrenergic innervation organs (Adrenal glands, salivary glands, heart and spleen)

Strategies for the solid-phase diversification of poly-L-proline-type II peptide mimic scaffolds and peptide scaffolds through guanidinylation.

Science.gov (United States)

Flemer, Stevenson; Wurthmann, Alexander; Mamai, Ahmed; Madalengoitia, José S

2008-10-03

A strategy for the solid-phase diversification of PPII mimic scaffolds through guanidinylation is presented. The approach involves the synthesis N-Pmc-N'-alkyl thioureas as diversification reagents. Analogues of Fmoc-Orn(Mtt)-OH can be incorporated into a growing peptide chain on Wang resin. Side chain deprotection with 1% TFA/CH2Cl2 followed by EDCI-mediated reaction of N-Pmc-N'-alkyl thioureas with the side chain amine affords arginine analogues with modified guanidine head groups. The scope, limitations, and incidental chemistry are discussed.

In vivo turnover of the basement membrane and other heparan sulfate proteoglycans of rat glomerulus

DEFF Research Database (Denmark)

Beavan, L A; Davies, M; Couchman, J R

1989-01-01

The metabolic turnover of rat glomerular proteoglycans in vivo was investigated. Newly synthesized proteoglycans were labeled during a 7-h period after injecting sodium [35S]sulfate intraperitoneally. At the end of the labeling period a chase dose of sodium sulfate was given. Subsequently......-propanesulfonate-4 M guanidine hydrochloride, a procedure which solubilized greater than 95% of the 35S-labeled macromolecules. Of these 11-13% was immunoprecipitated by an antiserum against heparan sulfate proteoglycan which, in immunolocalization experiments, showed specificity for staining the basement membrane...

Phase equilibria in a system of aqueous arginine with an octane solution of sulfonic acid

Science.gov (United States)

Kuvaeva, Z. I.; Koval'chuk, I. V.; Vodop'yanova, L. A.; Soldatov, V. S.

2013-05-01

The extraction of arginine (Arg) from aqueous salt (0.1 M NaCl) solutions with a sulfo extractant in a wide range of pH values and amino acid concentrations was studied. The 0.1 M solution of dinonylnaphthalenesulfonic acid (HD) in octane was used as an extractant. The degree of extraction was found to be high at pH 0.8-9.0. This can be explained by the effect of additional intermolecular interactions in the extractant phase involving the guanidine group of Arg.

Ring transformation of chromone-3-carboxamide under nucleophilic conditions

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Magdy A., E-mail: magdy_ahmed1977@yahoo.com [Department of Chemistry, Faculty of Education, Ain Shams University, Cairo(Egypt)

2013-11-15

The chemical reactivity of chromone-3-carboxamide was studied towards a series of nitrogen and carbon nucleophiles. Treatment of carboxamide with some primary amines gave chromane-2,4-diones. Condensation of carboxamide with hydrazine hydrate, phenyl hydrazine and hydroxylamine hydrochloride afforded chromenopyrazoles and chromenoisoxazole, respectively. Reaction of carboxamide with guanidine hydrochloride, cyanoguanidine and thiourea resulted in ring transformation producing chromenopyridines. The chemical behavior of carboxamide was also studied towards ethylenediamine, o-phenylenediamine, 2-aminophenol and 2-aminothiophenol. A variety of products were isolated from the reaction of carboxamide with some carbon nucleophiles. (author)

Improved colorimetric determination of serum zinc.

Science.gov (United States)

Johnson, D J; Djuh, Y Y; Bruton, J; Williams, H L

1977-07-01

We show how zinc may easily be quantified in serum by first using an optimum concentration of guanidine hydrochloride to cause release of zinc from proteins, followed by complexation of released metals with cyanide. The cyanide complex of zinc is preferentially demasked with chloral hydrate, followed by a colorimetric reaction between zinc and 4-(2-pyridylazo)resorcinol. This is a sensitive water-soluble ligand; its complex with zinc has an absorption maximum at 497 nm. Values found by this technique compare favorably with those obtained by atomic absorption spectroscopy.

Intersubunit ionic interactions stabilize the nucleoside diphosphate kinase of Mycobacterium tuberculosis

DEFF Research Database (Denmark)

Georgescauld, Florian; Moynie, Lucile; Habersetzer, Johann

2013-01-01

activity and for protein stability to thermal and chemical denaturation. We identified the intersubunit salt bridge Arg(80) -Asp(93) as essential for hexamer stability, compensating for the decreased intersubunit contact area. Breaking the salt bridge by the mutation D93N dramatically decreased protein...... of the wild type simultaneously occur at higher urea concentrations. The dissociation step was not observed in guanidine hydrochloride, suggesting that low concentration of salt may stabilize the hexamer. Indeed, guanidinium and many other salts stabilized the hexamer with a half maximum effect of about 0.1 M...

Super agonist actions of clothianidin and related compounds on the SAD beta 2 nicotinic acetylcholine receptor expressed in Xenopus laevis oocytes.

Science.gov (United States)

Ihara, Makoto; Matsuda, Kazuhiko; Shimomura, Masaru; Sattelle, David B; Komai, Koichiro

2004-03-01

To compare the actions of clothianidin, a neonicotinoid acting on insect nicotinic acetylcholine receptors, and related compounds with that of imidacloprid, the compounds were tested on the Drosophila SAD-chicken beta2 nicotinic acetylcholine receptor expressed in Xenopus laevis oocytes using two-electrode voltage-clamp electrophysiology. The maximum response of the SAD beta 2 nicotinic receptor to clothianidin was larger than that observed for acetylcholine. Ring breakage of the imidazolidine ring of imidacloprid resulting in the generation of a guanidine group was critical for this super agonist action.

Catalisadores heterogêneos para a produção de monoésteres graxos (biodiesel

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Claudiney Soares Cordeiro

2011-01-01

Full Text Available The recent increase in the world biodiesel demand, along with the need to reduce costs while improving the environmental sustainability of the entire biodiesel production chain, have led to the search for heterogeneous catalysts that would be efficient and highly amenable to recycling. Many classes of materials have been tested for these purposes. Among these are zeolites, ion-exchange resins, inorganic oxides, guanidines, metal complexes, layered compounds and ionic liquids. This review article describes the structure, properties, synthesis and performance of compounds that are catalytic active in both esterification and transesterification reactions.

Radiochemical and biological control of metaiodobenzyl-guanidine (MIBG) labeled with 131I

International Nuclear Information System (INIS)

Barboza, M.R.F.F. de; Muramoto, E.; Colturato, M.T.; Silva Valente Goncalves, R. da; Pereira, N.P.S. de; Almeida, M.A.T.M. de; Silva, C.P.G. da.

1988-07-01

This study shows the standardization of the radiochemical control of MIBG - 131 I in eletrophoretic system and also the biological control in Wistar rat for a period of time, not longer than 60 minutes after tracer administration. (author) [pt

DEVELOPMENT OF ANALYTICAL METHODS FOR DETERMINING SUPPRESSOR CONCENTRATION IN THE MCU NEXT GENERATION SOLVENT (NGS)

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, K.; Fondeur, F.; White, T.; Diprete, D.; Milliken, C.

2013-07-31

Savannah River National Laboratory (SRNL) was tasked with identifying and developing at least one, but preferably two methods for quantifying the suppressor in the Next Generation Solvent (NGS) system. The suppressor is a guanidine derivative, N,N',N"-tris(3,7-dimethyloctyl)guanidine (TiDG). A list of 10 possible methods was generated, and screening experiments were performed for 8 of the 10 methods. After completion of the screening experiments, the non-aqueous acid-base titration was determined to be the most promising, and was selected for further development as the primary method. {sup 1}H NMR also showed promising results from the screening experiments, and this method was selected for further development as the secondary method. Other methods, including {sup 36}Cl radiocounting and ion chromatography, also showed promise; however, due to the similarity to the primary method (titration) and the inability to differentiate between TiDG and TOA (tri-n-ocytlamine) in the blended solvent, {sup 1}H NMR was selected over these methods. Analysis of radioactive samples obtained from real waste ESS (extraction, scrub, strip) testing using the titration method showed good results. Based on these results, the titration method was selected as the method of choice for TiDG measurement. {sup 1}H NMR has been selected as the secondary (back-up) method, and additional work is planned to further develop this method and to verify the method using radioactive samples. Procedures for analyzing radioactive samples of both pure NGS and blended solvent were developed and issued for the both methods.

Protein conjugated with aldehydes derived from lipid peroxidation as an independent parameter of the carbonyl stress in the kidney damage

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Medina-Navarro Rafael

2011-11-01

Full Text Available Abstract Background One of the well-defined and characterized protein modifications usually produced by oxidation is carbonylation, an irreversible non-enzymatic modification of proteins. However, carbonyl groups can be introduced into proteins by non-oxidative mechanisms. Reactive carbonyl compounds have been observed to have increased in patients with renal failure. In the present work we have described a procedure designed as aldehyde capture to calculate the protein carbonyl stress derived solely from lipid peroxidation. Methods Acrolein-albumin adduct was prepared as standard at alkaline pH. Rat liver microsomal membranes and serum samples from patients with diabetic nephropathy were subjected to the aldehyde capture procedure and aldol-protein formation. Before alkalinization and incubation, samples were precipitated and redisolved in 6M guanidine. The absorbances of the samples were read with a spectrophotometer at 266 nm against a blank of guanidine. Results Evidence showed abundance of unsaturated aldehydes derived from lipid peroxidation in rat liver microsomal membranes and in the serum of diabetic patients with advanced chronic kidney disease. Carbonyl protein and aldol-proteins resulted higher in the diabetic nephropathy patients (p Conclusion The aldehyde-protein adduct represents a non oxidative component of carbonyl stress, independent of the direct amino acid oxidation and could constitute a practical and novelty strategy to measure the carbonyl stress derived solely from lipid peroxidation and particularly in diabetic nephropathy patients. In addition, we are in a position to propose an alternative explanation of why alkalinization of urine attenuates rhabdomyolysis-induced renal dysfunction.

Synthesis of 2-[4-(10H-Substituted Phenothiazine-3-yl-6-Pyrimidin-2-Phenylthiol/ol/amine/thiol] Pyrroles

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Meghasham Narule

2007-01-01

Full Text Available 2-[4-Hydroxy benz-1(propene-1-one]Pyrrole II on treatment with phenyl thiourea, guanidine carbonate, urea and thiourea in alcoholic KOH yielded compounds III, IV, V, VI which on treatment with different aryl anilines gave compounds VII, VIII, IX, X which under goes cyclisation with sulphur and iodine to give 2-[4-(10H-substituted phenothiazine-3-yl-6-pyrimidin-2-phenylthiol/-ol/-amine/-thiol] pyrrole XI(a-j, XII(a-j, XIII(a-j and XIV(a-j respectively. The structural products were characterized by elemental analysis and spectral data.

Leading safety performance indicators for resilience assessment of radiopharmaceuticals production process

International Nuclear Information System (INIS)

Grecco, Claudio H.S.; Santos, Isaac J.A.L.; Carvalho, Paulo V.R.

2011-01-01

Radiopharmaceuticals are radiation-emitting substances used in medicine for radiotherapy and imaging diagnosis. A Research Institute, located in Rio de Janeiro, produces three radiopharmaceuticals: the sodium iodate is used in the diagnosis of thyroid dysfunctions, the meta-iodo-benzyl guanidine is used in the diagnosis of cardiac diseases, and the fluorodeoxyglucose is used in diagnosis in cardiology, oncology, neurology and neuro psychiatry. This paper presents a leading safety performance indicators framework to assess the resilience of radiopharmaceuticals production processes. The organizations that use resilience indicators will be able to pro actively evaluate and manage safety. (author)

Leading safety performance indicators for resilience assessment of radiopharmaceuticals production process

Energy Technology Data Exchange (ETDEWEB)

Grecco, Claudio H.S.; Santos, Isaac J.A.L.; Carvalho, Paulo V.R., E-mail: grecco@ien.gov.b, E-mail: luquetti@ien.gov.b, E-mail: paulov@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Instrumentacao e Confiabilidade Humana; Vidal, Mario C.R., E-mail: mvidal@ergonomia.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEP/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia de Producao. Grupo de Ergonomia e Novas Tecnologias (GENTE)

2011-07-01

Radiopharmaceuticals are radiation-emitting substances used in medicine for radiotherapy and imaging diagnosis. A Research Institute, located in Rio de Janeiro, produces three radiopharmaceuticals: the sodium iodate is used in the diagnosis of thyroid dysfunctions, the meta-iodo-benzyl guanidine is used in the diagnosis of cardiac diseases, and the fluorodeoxyglucose is used in diagnosis in cardiology, oncology, neurology and neuro psychiatry. This paper presents a leading safety performance indicators framework to assess the resilience of radiopharmaceuticals production processes. The organizations that use resilience indicators will be able to pro actively evaluate and manage safety. (author)

Enriched reaction center preparation from green photosynthetic bacteria. [Chlorobium limicola

Energy Technology Data Exchange (ETDEWEB)

Olson, J M; Giddings, Jr, T H; Shaw, E K

1976-01-01

Bacteriochlorophyll a reaction-center complex I from Chlorobium limicola f. thiosulfatophilum 6230 (Tassajara) was incubated in 2 M guanidine . HCl and then chromatographed on cross-linked dextran or agarose gel. Two principal components were separated: a larger component with photochemical activity (bacteriochlorophyll a reaction-center complex II) and a smaller component without activity (bacteriochlorophyll a protein). Complex II contains carotenoid, bacteriochlorophyll a, reaction center(s), and cytochromes b and c, but lacks the well characterized bacteriochlorophyll a protein contained in Complex I. Complex II carries out a light-induced reduction of cytochrome b along with an oxidation of cytochrome c.

Distribution, transition and thermodynamic stability of protein conformations in the denaturant-induced unfolding of proteins.

Science.gov (United States)

Bian, Liujiao; Ji, Xu

2014-01-01

Extensive and intensive studies on the unfolding of proteins require appropriate theoretical model and parameter to clearly illustrate the feature and characteristic of the unfolding system. Over the past several decades, four approaches have been proposed to describe the interaction between proteins and denaturants, but some ambiguity and deviations usually occur in the explanation of the experimental data. In this work, a theoretical model was presented to show the dependency of the residual activity ratio of the proteins on the molar denaturant concentration. Through the characteristic unfolding parameters ki and Δmi in this model, the distribution, transition and thermodynamic stability of protein conformations during the unfolding process can be quantitatively described. This model was tested with the two-state unfolding of bovine heart cytochrome c and the three-state unfolding of hen egg white lysozyme induced by both guanidine hydrochloride and urea, the four-state unfolding of bovine carbonic anhydrase b induced by guanidine hydrochloride and the unfolding of some other proteins induced by denaturants. The results illustrated that this model could be used accurately to reveal the distribution and transition of protein conformations in the presence of different concentrations of denaturants and to evaluate the unfolding tendency and thermodynamic stability of different conformations. In most denaturant-induced unfolding of proteins, the unfolding became increasingly hard in next transition step and the proteins became more unstable as they attained next successive stable conformation. This work presents a useful method for people to study the unfolding of proteins and may be used to describe the unfolding and refolding of other biopolymers induced by denaturants, inducers, etc.

Dissipation kinetics and effect of processing on imidacloprid and its metabolites in cardamom (Elettaria cardamomum Maton).

Science.gov (United States)

Pratheeshkumar, N; Chandran, M; Beevi, S Naseema; Mathew, Thomas Biju; George, Thomas; Paul, Ambily; Xavier, George; Ravi, K Prathibha; Kumar, S Visal; Rajith, R

2016-01-01

Dissipation behaviour of the chloronicotinyl insecticide, imidacloprid (Tatamida 17.8 % SL), in fresh and cured cardamom capsules was studied following application at doses 20 and 40 g a.i. ha(-1) in a cardamom plantation of Indian Cardamom Hills (ICH), Idukki, Kerala, India. A single-laboratory ultra performance liquid chromatography mass spectrometry (UPLC-MS/MS) method was developed and validated for the estimation of imidacloprid and its six metabolites (5-hydroxy, olefin, guanidine, urea, 6-chloronicotinic acid and nitrosimine) in fresh and cured cardamom. At the lower dose, the initial deposits of total imidacloprid residues were 1.91 and 7.23 μg g(-1), respectively, in fresh and cured cardamom. At the higher dose, the initial residues were 3.94 and 14.72 μg g(-1), respectively, in fresh and cured capsules. The residues dissipated below the quantitation level of 0.01 μg g(-1) after 21 and 28 days at lower dose and after 28 days for both at higher dose. The half-lives of imidacloprid in fresh and cured cardamom were 4.02 and 3.63 days, respectively, at lower dose and 3.61 days for both at higher dose. The waiting periods of imidacloprid on fresh and cured cardamom at lower and higher doses were 21.40, 27.10, 23.85 and 30.70 days, respectively. The mean processing factor of imidacloprid was 3.96 at 20 g a.i. ha(-1). Amongst metabolites of imidacloprid, urea had maximum residues in fresh and cured cardamom followed by 5-hydroxy and guanidine. Other metabolites such as 6-chloronicotinic acid, olefin and nitrosimine were not detected either in fresh or cured cardamom.

Enamel formation in vitro in mouse molar explants exposed to amelogenin polypeptides ATMP and LRAP on enamel development.

Science.gov (United States)

Ravindranath, Rajeswari M H; Devarajan, Asokan; Bringas, Pablo

2007-12-01

The enamel matrix contains amelogenin, leucine-rich amelogenin-polypeptide (LRAP), resulting from alternative splicing of the primary amelogenin-RNA transcript and tyrosine-rich amelogenin-polypeptide (TRAP), a proteolytic product of amelogenin. Presence of amelogenin-trityrosyl-motif peptide (ATMP) distinguishes TRAP from LRAP. The roles of these polypeptides in the formation of enamel remain to be elucidated. The mouse in vitro molar tooth-organ developed from bud stage (E16) was exposed to LRAP, ATMP, and mutated ATMP (T-ATMP, third proline replaced by threonine). The histology and morphometry of the explants on day-12 in culture was examined using Mallory's stain. Guanidine-HCl soluble protein concentrations of explants were compared. The enamel width and protein solubility indicate that the explant on day-12 is comparable to postnatal molar on day-3 in vivo. The enamel of both untreated explants as well as that in vivo is fuchinophilic (acid fuchsin, AF+). ATMP reduced the ameloblast-height, accumulated AF+ spherules at the apical end of ameloblasts, and disrupted enamel-dentin bonding. T-ATMP abrogated deposition of AF+ material on the aniline blue positive (AB+) enamel matrix. LRAP reduced ameloblast-height, increased the enamel-width without disruption (at 17.25 nmol) and increased the density of AF+ dentinal tubules. AF+ substance from the tubules is released onto the surface of the dentin. The Guanidine-HCl-soluble protein is elevated in ATMP-treated explants but decreased in LRAP-treated explants. Exogenous ATMP, T-ATMP and LRAP have divergent effects on developing enamel. Exogenous ATMP, but not LRAP, abrogates enamel-dentin bonding at 17.25 nmol. LRAP may play a role in the differentiation of ameloblasts, growth of enamel and formation of dentinal tubules.

Selective mode of action of guanidine-containing non-peptides at human NPFF receptors.

Science.gov (United States)

Findeisen, Maria; Würker, Cäcilia; Rathmann, Daniel; Meier, René; Meiler, Jens; Olsson, Roger; Beck-Sickinger, Annette G

2012-07-12

The binding pocket of both NPFF receptors was investigated, focusing on subtype-selective behavior. By use of four nonpeptidic compounds and the peptide mimetics RF9 and BIBP3226, agonistic and antagonistic properties were characterized. A set of Ala receptor mutants was generated. The binding pocket was narrowed down to the upper part of transmembrane helices V, VI, VII and the extracellular loop 2. Positions 5.27 and 6.59 have been shown to have a strong impact on receptor activation and were suggested to form an acidic, negatively charged binding pocket in both NPFF receptor subtypes. Additionally, position 7.35 was identified to play an important role in functional selectivity. According to docking experiments, the aryl group of AC-216 interacts with position 7.35 in the NPFF(1) but not in the NPFF(2) receptor. These results provide distinct insights into the receptor specific binding pockets, which is necessary for the development of drugs to address the NPFF system.

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

DEFF Research Database (Denmark)

Kistrup, Kasper; Sørensen, Karen Skotte; Wolff, Anders

2014-01-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible......-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis...

The use of carrier RNA to enhance DNA extraction from microfluidic-based silica monoliths.

Science.gov (United States)

Shaw, Kirsty J; Thain, Lauren; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2009-10-12

DNA extraction was carried out on silica-based monoliths within a microfluidic device. Solid-phase DNA extraction methodology was applied in which the DNA binds to silica in the presence of a chaotropic salt, such as guanidine hydrochloride, and is eluted in a low ionic strength solution, such as water. The addition of poly-A carrier RNA to the chaotropic salt solution resulted in a marked increase in the effective amount of DNA that could be recovered (25ng) compared to the absence of RNA (5ng) using the silica-based monolith. These findings confirm that techniques utilising nucleic acid carrier molecules can enhance DNA extraction methodologies in microfluidic applications.

Reações de organocatálise com aminas quirais: aspectos mecanísticos e aplicações em síntese orgânica Organocatalysis reactions with chiral amines: mechanistic aspects and use on organic synthesis

Directory of Open Access Journals (Sweden)

Giovanni W. Amarante

2009-01-01

Full Text Available The philosophy of organocatalysis is based on the utilization of organic compounds to catalyze organic transformations without the intervention of metals. This area has attracted much attention of the synthetic chemistry community on the last years, which can be confirmed by the explosion of published papers dealing with this subject. Phosphorus compounds, urea and thiourea derivatives, alkaloids, guanidine derivatives, for example, have already been used as organocatalysts. In this review we have focused on the use of chiral amines as organocatalyst. We have also chosen some outstanding examples to demonstrate the potentiality of this strategy in the synthesis of natural products and biologically active compounds.

Synthesis and Antibacterial Evaluation of Novel Heterocyclic Compounds Containing a Sulfonamido Moiety

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Eman A. El-Bordany

2013-01-01

Full Text Available Aiming for the synthesis of new heterocyclic compounds containing a sulfonamido moiety suitable for use as antibacterial agents, the precursor ethyl {[4-N-(4,6-dimethylpyrimidin-2-ylsulfamoyl]phenylazo}cyanoacetate was reacted with a variety of active methylene compounds producing pyran, pyridine and pyridazine derivatives. Also, the reactivity of the precursor hydrazone towards hydrazine derivatives to give pyrazole and oxazole derivatives was studied. On the other hand, treatment of the same precursor with urea, thiourea and/or guanidine hydrochloride furnished pyrimidine and thiazine derivatives, respectively. The newly synthesized compounds were tested for antibacterial activity, whereby eight compounds were found to have high activities.

Investigations into the influence of some synergists of 2,4-dioxo-hexahydro-1,3,5-triazine (DHT) on the formation of 14CO2 from [2,4-14C]DHT

International Nuclear Information System (INIS)

Byhan, O.; Schuster, G.

1986-01-01

Combined treatment with DHT and N-phenyl-N'-p-carboxyphenyl-thiourea reduced the formation of 14 CO 2 from [2,4- 14 C]DHT. Contrary to this, combined treatments with N-phenyl-N'-p-carboxyphenyl-urea, cyanoguanidine and, above all, guanidine carbonate increased the formation of 14 CO 2 from [2,4- 14 C]DHT. Thus, retardation of the breakdown of DHT and, beside this, maintenance of a high concentration of DHT, can only be the reason for the augmentation of the antiphytoviral activities of DHT by N-phenyl-N'-p-carboxyphenylthiourea, but not for that by the other 3 substances. An alternative hypothesis is discussed. (author)

Dragmacidin G, a Bioactive Bis-Indole Alkaloid from a Deep-Water Sponge of the Genus Spongosorites.

Science.gov (United States)

Wright, Amy E; Killday, K Brian; Chakrabarti, Debopam; Guzmán, Esther A; Harmody, Dedra; McCarthy, Peter J; Pitts, Tara; Pomponi, Shirley A; Reed, John K; Roberts, Bracken F; Rodrigues Felix, Carolina; Rohde, Kyle H

2017-01-11

A deep-water sponge of the genus Spongosorites has yielded a bis-indole alkaloid which we have named dragmacidin G. Dragmacidin G was first reported by us in the patent literature and has recently been reported by Hitora et al. from a sponge of the genus Lipastrotheya . Dragmacidin G is the first in this series of compounds to have a pyrazine ring linking the two indole rings. It also has a rare N -(2-mercaptoethyl)-guanidine side chain. Dragmacidin G shows a broad spectrum of biological activity including inhibition of methicillin-resistant Staphylococcus aureus , Mycobacterium tuberculosis , Plasmodium falciparum, and a panel of pancreatic cancer cell lines.

Dragmacidin G, a Bioactive Bis-Indole Alkaloid from a Deep-Water Sponge of the Genus Spongosorites

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Amy E. Wright

2017-01-01

Full Text Available A deep-water sponge of the genus Spongosorites has yielded a bis-indole alkaloid which we have named dragmacidin G. Dragmacidin G was first reported by us in the patent literature and has recently been reported by Hitora et al. from a sponge of the genus Lipastrotheya. Dragmacidin G is the first in this series of compounds to have a pyrazine ring linking the two indole rings. It also has a rare N-(2-mercaptoethyl-guanidine side chain. Dragmacidin G shows a broad spectrum of biological activity including inhibition of methicillin-resistant Staphylococcus aureus, Mycobacterium tuberculosis, Plasmodium falciparum, and a panel of pancreatic cancer cell lines.

Organo catalysis reactions with chiral amines: mechanistic aspects and uses on organic synthesis; Reacoes de organocatalise com aminas quirais: aspectos mecanisticos e aplicacoes em sintese organica

Energy Technology Data Exchange (ETDEWEB)

Amarante, Giovanni W.; Coelho, Fernando [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica]. E-mail: coelho@iqm.unicamp.br

2009-07-01

The philosophy of organocatalysis is based on the utilization of organic compounds to catalyze organic transformations without the intervention of metals. This area has attracted much attention of the synthetic chemistry community on the last years, which can be confirmed by the explosion of published papers dealing with this subject. Phosphorus compounds, urea and thiourea derivatives, alkaloids, guanidine derivatives, for example, have already been used as organocatalysts. In this review we have focused on the use of chiral amines as organocatalyst. We have also chosen some outstanding examples to demonstrate the potentiality of this strategy in the synthesis of natural products and biologically active compounds. (author)

Syntheses and anti-microbial evaluation of new quinoline scaffold derived pyrimidine derivatives

Directory of Open Access Journals (Sweden)

Shikha S. Dave

2016-09-01

Full Text Available A series of diversely substituted chalcones derived from a quinoline scaffold, e.g. (E-3-(2-chloroquinolin-3-yl-1-(2-hydroxyphenyl prop-2-en-1-one and its pyrimidine analogues e.g. 2-[2-amino-6-(2-chloroquinolin-3-yl-5,6-dihydropyrimidin-4-yl]phenols have been prepared by condensation of 2-chloro-3-formyl quinoline with differently substituted 2-hydroxy acetophenones and further treatment with guanidine carbonate. All the newly synthesized compounds have been evaluated for their in vitro growth inhibitory activity against Escherichia coli, Pseudomonas vulgaris, Bacillus subtilis, Staphylococcus aureus, Staphylococcus typhi, Candida albicans, Aspergillus niger and Pseudomonas chrysogenum.

Template synthesis and characterization of nanostructured hierarchical mesoporous ribbon-like NiO as high performance electrode material for supercapacitor

International Nuclear Information System (INIS)

Yao, Mingming; Hu, Zhonghua; Xu, Zijie; Liu, Yafei; Liu, Peipei; Zhang, Qiang

2015-01-01

The ribbon-like NiO was synthesized by a hard-template method combining the calcination, using mesoporous carbon as a hard templat and guanidine hydrochloride as precipitant of weak base, respectively. The nanostructured hierarchical mesoporous ribbon-like NiO exhibits the high specific capacitance of 1260 F g −1 at the current density of 1 A g −1 , and 95% capacity retention at a current density of 10 A g −1 in a testing range of 5000 cycles. - Highlights: • Ribbon-like NiO was prepared by using mesoporous carbon as a hard template. • Typical ribbon-like NiO possesses the hierarchical mesoporous nanostructure. • High specific capacitance of 1260 F g −1 is obtained at a current density of 1 A g −1 . • Excellent electrochemical stability of 95% after 5000 charge–discharge cycles. - Abstract: In this paper, nanostructured hierarchical mesoporous ribbon-like NiO was synthesized by a hard-template method combining the calcination process. Nickel sulfate hexahydrate, guanidine hydrochloride and mesoporous carbon were used as nickel precursors, precipitant of weak base and template, respectively. The resultant NiO samples were characterized by Raman spectroscopy, energy dispersive spectrometer, X-ray diffraction, N 2 adsorption and desorption, scanning electron microscopy and transmission electron microscopy. The electrochemical performances were evaluated by cyclic voltammetry (CV), cyclic chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) in 6 M KOH solution. The typical hierarchical mesoporous ribbon-like NiO shows a good electrochemical performance: a high specific capacitance of 1260 F g −1 at 1 A g −1 , 748 F g −1 at high current density of 20 A g −1 and 95% capacity retention at a current density of 10 A g −1 in a testing range of 5000 cycles

Humidifier disinfectant lung injury, how do we approach the issues?

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Jihyun Emma Choi

2016-08-01

Full Text Available A large portion of the Korean population has been exposed to toxic humidifier disinfectants (HDs, and considering that the majority of the victims are infants, the magnitude of the damage is expected to be considerably larger than what has currently been revealed. The current victims are voicing problems caused by various diseases, including but not limited to lung, upper respiratory tract, cardiovascular, kidney, musculoskeletal, eye, and skin diseases, etc. However, there has been difficulty in gaining validation for these health problems and identifying causal relationships due to lack of evidence proving that toxic HD is the specific causes of extrapulmonary diseases such as allergic rhinitis. Furthermore, the victims and bereaved families of the HD case have not received any support for psychological distress such as post-traumatic stress disorder, depression, feelings of injustice, and anger caused by the trauma. In addition, because the underlying mechanisms of the toxic materials within the HDs such as polyhexamethylene guanidine phosphate, poly(oxyalkylene guanidine hydrochloride, chloromethylisothiazolinone/methylisothiazolinone have yet to be determined, the demand for information regarding the HD issue is growing. The victims of the HD cases require support that goes beyond financial aid for medical costs and living expenses. There is a desperate need for government-led integrated support centers that provide individualized support through health screenings; in other words, we need an integrated facility that provides the appropriate social support to allow the victims to recover their physical and mental health, so as to well prepare them to return to a normal life. The implementation of such a plan requires not only the close cooperation between those departments already directly involved such as the Ministry of Environment and the Ministry of Health and Welfare, but also active support on a national scale from pan

Kinetic Stability May Determine the Interaction Dynamics of the Bifunctional Protein DCoH1, the Dimerization Cofactor of the Transcription Factor HNF-1[alpha

Energy Technology Data Exchange (ETDEWEB)

Rho, H.; Jones, C.N.; Rose, R.B. (NCSU)

2010-12-07

The two disparate functions of DCoH1 (dimerization cofactor of HNF-1)/PCD (pterin-4a-carbinolamine dehydratase) are associated with a change in oligomeric state. DCoH dimers enhance the activity of the diabetes-associated transcription factor HNF-1{alpha} (hepatocyte nuclear factor-1{alpha}), while the PCD activity of DCoH1 homotetramers aids in aromatic amino acid metabolism. These complexes compete for the same interface of the DCoH dimer. Formation of the DCoH1/HNF-1{alpha} complex requires cofolding. The homotetramer of the DCoH1 paralogue, DCoH2, interacts with HNF-1{alpha} through simple mixing. To further investigate regulation of DCoH/HNF-1{alpha} complex formation, we measured the stability of the DCoH1 homotetramer through unfolding studies by intrinsic tryptophan fluorescence. DCoH2 unfolding is reversible. Surprisingly, the DCoH1 homotetramer is resistant to guanidine unfolding but refolds at a much lower guanidine concentration. We show that a point mutation at the DCoH1 tetramer interface, Thr 51 Ser, overcomes the dissociation barrier of the homotetramer and increases the interaction with HNF-1{alpha}. The 1.8 {angstrom} resolution crystal structure of DCoH1 T51S shows the presence of an ordered water molecule at the tetramer interface, as in DCoH2, which may destabilize the homotetramer. The equilibrium unfolding data were fit to a two-state model with no apparent intermediate. Folding intermediates were detectable by size exclusion chromatography. For wild-type DCoH1 the intermediates changed with time, suggesting a kinetic origin for the unfolding barrier of the homotetramer. We propose an unfolding pathway in which the tetramer unfolds slowly, but the dimer folds reversibly. Implications for regulation of DCoH1/HNF-1{alpha} complex formation are discussed.

Platinum(II) complexes as spectroscopic probes for biomolecules

Energy Technology Data Exchange (ETDEWEB)

Ratilla, E.

1990-09-21

The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

Heart failure and 1231-M.I.B.G. scintigraphy: comeback; Scintigraphie cardiaque a la 1231-metaiodobenzylguanidine et cardiomyopathies: le retour

Energy Technology Data Exchange (ETDEWEB)

Agostini, D.; Hugentobler, A.; Costo, S.; Bouvard, G. [Centre Hospitalier Universitaire Cote de Nacre, Service de Medecine Nucleaire, 14 - Caen (France); Manrique, A. [Centre de Lutte Contre le Cancer Henri-Becquerel, Service de Medecine Nucleaire, 76 - Rouen (France); Sabatier, R.; Grollier, G. [Centre Hospitalier Universitaire Cote de Nacre, Service de Cardiologie, 14 - Caen (France); Belin, A. [Hopital de Trouville, Service de Readaptation Cardiaque, 14 - Trouville (France)

2007-09-15

Congestive heart failure is a often associated with an impairment of sympathetic nervous system, i.e., global hyperactivity and regional impairment of adrenergic system. Cardiac {sup 123}I-meta-iodo-benzyl-guanidine (M.I.B.G.) scintigraphy is a radionuclide technique which can explore the presynaptic adrenergic function. Cardiac fixation of M.I.B.G. is decreased in congestive heart failure, reflecting a reduction of norepinephrine uptake by the myocardial presynaptic ending nerves. The impairment of presynaptic function is early and actually involved in the pathogenesis of cardiac failure. Cardiac M.I.B.G. scintigraphy is a useful tool to explore the myocardial adrenergic stores in patients with congestive heart failure. (authors)

Circular Permutation of a Chaperonin Protein: Biophysics and Application to Nanotechnology

Science.gov (United States)

Paavola, Chad; Chan, Suzanne; Li, Yi-Fen; McMillan, R. Andrew; Trent, Jonathan

2004-01-01

We have designed five circular permutants of a chaperonin protein derived from the hyperthermophilic organism Sulfolobus shibatae. These permuted proteins were expressed in E. coli and are well-folded. Furthermore, all the permutants assemble into 18-mer double rings of the same form as the wild-type protein. We characterized the thermodynamics of folding for each permutant by both guanidine denaturation and differential scanning calorimetry. We also examined the assembly of chaperonin rings into higher order structures that may be used as nanoscale templates. The results show that circular permutation can be used to tune the thermodynamic properties of a protein template as well as facilitating the fusion of peptides, binding proteins or enzymes onto nanostructured templates.

Molecular precursors for the phase-change material germanium-antimony-telluride, Ge{sub 2}Sb{sub 2}Te{sub 5} (GST)

Energy Technology Data Exchange (ETDEWEB)

Harmgarth, Nicole; Zoerner, Florian; Engelhardt, Felix; Edelmann, Frank T. [Chemisches Institut, Otto-von-Guericke-Universitaet Magdeburg (Germany); Liebing, Phil [Laboratorium fuer Anorganische Chemie, ETH Zuerich (Switzerland); Burte, Edmund P.; Silinskas, Mindaugas [Institut fuer Mikro- und Sensorsysteme, Otto-von-Guericke-Universitaet Magdeburg (Germany)

2017-10-04

This review provides an overview of the precursor chemistry that has been developed around the phase-change material germanium-antimony-telluride, Ge{sub 2}Sb{sub 2}Te{sub 5} (GST). Thin films of GST can be deposited by employing either chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques. In both cases, the success of the layer deposition crucially depends on the proper choice of suitable molecular precursors. Previously reported processes mainly relied on simple alkoxides, alkyls, amides and halides of germanium, antimony, and tellurium. More sophisticated precursor design provided a number of promising new aziridinides and guanidinates. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis and Evaluation of Curcuminoid Analogues as Antioxidant and Antibacterial Agents

Directory of Open Access Journals (Sweden)

Dalia R. Emam

2017-06-01

Full Text Available Diazocoupling reaction of curcumin with different diazonium salts of p-toluidine, 2-aminopyridine, and 4-aminoantipyrine in pyridine yielded the arylhydrazones 2a–c. Arylhydrazone of p-toluidine reacted with urea, thiourea, and guanidine nitrate to produce 5,6-dihydropyrimidines. Further reaction of 2a with 2,3-diaminopyrdine in sodium ethoxide solution yielded 1H-pyrido[2,3-b][1,4]diazepine derivative. Bis(2,5-dihydroisoxazole is obtained from the reaction of 2a with hydroxylamine hydrochloride, while its reactions with hydrazines afforded the respective 4,5-dihydro-1H-pyrazoles. The target compounds were evaluated as antioxidant and antibacterial agents. The tested compounds showed good to moderate activities compared to ascorbic acid and chloramphenicol, respectively.

N(G)-Acyl-argininamides as NPY Y(1) receptor antagonists: Influence of structurally diverse acyl substituents on stability and affinity.

Science.gov (United States)

Weiss, Stefan; Keller, Max; Bernhardt, Günther; Buschauer, Armin; König, Burkhard

2010-09-01

N(G)-Acylated argininamides, covering a broad range of lipophilicity (calculated logD values: -1.8-12.5), were synthesized and investigated for NPY Y(1) receptor (Y(1)R) antagonism, Y(1)R affinity and stability in buffer (N(G)-deacylation, yielding BIBP 3226). Broad structural variation of substituents was tolerated. The K(i) (binding) and K(b) values (Y(1)R antagonism) varied from low nM to one-digit muM. Most of the compounds proved to be sufficiently stable at pH 7.4 over 90min to determine reliable pharmacological data in vitro. Exceptionally high instability was detected when a succinyl moiety was attached to the guanidine, probably, due to an intramolecular cleavage mechanism. Copyright 2010 Elsevier Ltd. All rights reserved.

Quantitation of yeast total proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis sample buffer for uniform loading.

Science.gov (United States)

Sheen, Hyukho

2016-04-01

Proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample buffer are difficult to quantitate due to SDS and reducing agents being in the buffer. Although acetone precipitation has long been used to clean up proteins from detergents and salts, previous studies showed that protein recovery from acetone precipitation varies from 50 to 100% depending on the samples tested. Here, this article shows that acetone precipitates proteins highly efficiently from SDS-PAGE sample buffer and that quantitative recovery is achieved in 5 min at room temperature. Moreover, precipitated proteins are resolubilized with urea/guanidine, rather than with SDS. Thus, the resolubilized samples are readily quantifiable with Bradford reagent without using SDS-compatible assays. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of an antibody avidity index method for detecting recent human immunodeficiency virus type 1 infection using an automated chemiluminescence immunoassay.

Science.gov (United States)

Fernández, Gema; Manzardo, Christian; Montoliu, Alexandra; Campbell, Colin; Fernández, Gregorio; Casabona, Jordi; Miró, José Maria; Matas, Lurdes; Rivaya, Belén; González, Victoria

2015-04-01

Recent infection testing algorithms (RITAs) are used in public health surveillance to estimate the incidence of recently acquired HIV-1 infection. Our aims were (i) to evaluate the precision of the VITROS® Anti-HIV 1+2 automated antibody avidity assay for qualitative detection of antibodies to HIV 1+2 virus; (ii) to validate the accuracy of an automated guanidine-based antibody avidity assay to discriminate between recent and long standing infections using the VITROS 3600 platform; (iii) to compare this method with BED-CEIA assay; and (iv) to evaluate the occurrence of false recent misclassifications by the VITROS antibody avidity assay in patients with a CD4 count de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Evaluation of diabetic autonomic neuropathy by 123I-metaiodobenzyl-guanidine (MIBG) cardiac imaging. Initial report

International Nuclear Information System (INIS)

Osonoi, Takeshi; Fukumoto, Yoshihiro; Saitou, Miyoko; Kuroda, Yasuhisa; Uchimi, Nobuo; Ishioka, Kuniharu; Onuma, Tomio; Suga, Shigeki; Takebe, Kazuo.

1994-01-01

Single-photon emission computed tomography was performed in 52 diabetics and 10 healthy volunteers using MIBG. The diabetics had no particular findings of electrocardiography, echocardiography, or exercise thallium imaging and no cardiovascular episodes. The healthy volunteers had no abnormal findings on exercise thallium imaging or glucose tolerance test. The average relative regional uptake (RRU) was decreased in the inferoposterior wall compared with the anterior or lateral wall in both the diabetics and volunteers. According to the RRU and visual images, we divided the diabetics into the following four groups: 14 who were normal (group N), 30 with segmental defects (group S), 4 with diffuse defects (group D) and 4 without accumulation (group DH). Diabetic complications (retinopathy, nephropathy, and neuropathy) and hypertension were more frequent in group S than group N. However, there were no significant differences in the physiological evidence of autonomic neuropathy (C.V. of the R-R interval on the ECG and blood pressure response to standing or deep breathing) between groups S and N. Vibration sense was significantly more impaired in group S than in group N. These results suggest that cardiac imaging with MIBG might be a useful examination for the early diagnosis of diabetic autonomic neuropathy. (author)

Recommendation for KIT-formulation of radioiodinated [*I] meta-iodo benzyl guanidine (M*IBG). Vol. 3

International Nuclear Information System (INIS)

El-shaboury, G.; El-Kolaly, M.T.; Raieh, M.; El-Bayoumy, S.; Zakareia, N.

1996-01-01

A recommended simple technique for preparation of radioiodinated [ * I - ] meta - iodobenzylguanidine (M * IBG) is presented. The technique is based on a schematic procedure for the synthesis of inactive M IBG using meta -iodo benzoic as substrate, results into a chemical yield of 80% as pure as M IBG 0.5 substrate, then recrystallized from water - ethyl alcohol as crystalline powder of M.P. 165 Degree C - 167 degree C. The radioiodination process is performed through an isotropic exchange reaction between the inactive M IBG and radioiodine as iodine ion ( * I - ) in 0.2 M acetate buffer pH 4.2 - 4.25 at 100 degree C within 30 min in the presence of metal as exchange catalyst. Following these processes, the reaction solution is allowed for purification by passing it through an AgCl - impregnated filter to remove the unreacted radioiodine as Ag * I (5%). According of these results and reaction conditions it was possible to develop a technology for the radiopharmaceutical production of radioiodinated M * IBG using the currently used short - lived radioiodine nuclides by a simple kit like - type technique, where the radiochemical yield % is 95 - 99% as pure as M * IBG. 5 figs., 3 tabs

Role of Radio-Iodinated Meta-Iodo Benzyl Guanidine in Assessment of Children with Neuroblastoma NEMROCK

International Nuclear Information System (INIS)

Abd El-Aal, H.

2006-01-01

Background: For more than ten years. M] BG has been successfully used in diagnosis and staging of children with neuroblastoma [1]. Aim of the Study: Identify the role of 131 I MIBG in the assessment of neuroblastoma and correlate its findings with other non-invasive tests. Patients and Methods: Twenty eight patients with. neuroblastoma attending the Pediatric Oncology Unit, Kasr EI-Aini Center of Radiation Oncology and Nuclear Medicine (NEMROCK), Cairo University, over a period of 5 years (2002-2006) were assessed by MlBG scanning. The age of patients ranged from 40 days to 12 years with a mean of 4.7years ± 1.1. They were 16 boys and 12 girls with a M:F ratio of J :3, none was stage I and II, 7 patients (25%) were stage III and 21 patients (75%) were stage IV (Evan's staging system). Clinically, 24 patients (85.7%) presented with an abdominal mass, and 3 patients (10.7%) with a mediastinal mass. Metastases were present in the bone marrow in II children (39.3%), lymph nodes in 5 (17.9%), CNS in 4 (14.3%), liver in 2 (7.1 %), soft tissues in 3 (10.7%), lungs and pleura in I (3.6%), brain in I (3.6%), and testis in I patient (3.8%). Results: 131 I M IBG could accurately diagnose local and distant neuroblastoma lesions in 23 patients with a sensitivity of 82.2%. High levels of VMA correlated with no cardiac uptake in the first 24 hours in 7/8 patients with a sensitivity of 87.5%. On the other hand, low VMA levels were associated with cardiac uptake of 131 I MIBG in 3/4 patients with a specificity of 75%, a PPV of 88% and NPV of 86.7%. 131 I MlBG scintigraphy and bone marrow aspiration agreed on detecting neuroblastoma lesions in 24/28 patients (85.7%) p 131 I MIBG scintigraphy, in a dose of 2 mci can be used with 87.5% accuracy in the diagnosis and follow-up of Children with neuroblastoma

Evaluation of the furosine and homoarginine methods for determining reactive lysine in rumen-undegraded protein.

Science.gov (United States)

Boucher, S E; Pedersen, C; Stein, H H; Schwab, C G

2009-08-01

Three samples of soybean meal (SBM), 3 samples of expeller SBM (SoyPlus, West Central Cooperative, Ralston, IA), 5 samples of distillers dried grains with solubles (DDGS), and 5 samples of fish meal were used to evaluate the furosine and homoarginine procedures to estimate reactive Lys in the rumen-undegraded protein fraction (RUP-Lys). One sample each of SBM, expeller SBM, and DDGS were subjected to additional heat treatment in the lab to ensure there was a wide range in reactive RUP-Lys content among the samples. Furosine is a secondary product of the initial stages of the Maillard reaction and can be used to calculate blocked Lys. Homoarginine is formed via the reaction of reactive Lys with O-methylisourea and can be used to calculate the concentration of reactive Lys. In previous experiments, each sample was ruminally incubated in situ for 16 h, and standardized RUP-Lys digestibility of the samples was determined in cecectomized roosters. All rumen-undegraded residue (RUR) samples were analyzed for furosine and Lys; however, only 9 of the 16 samples contained furosine, and only the 4 unheated DDGS samples contained appreciable amounts of furosine. Blocked RUP-Lys was calculated from the furosine and Lys concentrations of the RUR. Both the intact feed and RUR samples were evaluated using the homoarginine method. All samples were incubated with an O-methylisourea/BaOH solution for 72 h and analyzed for Lys and homoarginine concentrations. Reactive Lys concentrations of the intact feeds and RUR were calculated. Results of the experiment indicate that blocked RUP-Lys determined via the furosine method was negatively correlated with standardized RUP-Lys digestibility, and reactive RUP-Lys determined via the guanidination method was positively correlated with standardized RUP-Lys digestibility. Reactive Lys concentrations of the intact samples were also highly correlated with RUP-Lys digestibility. In conclusion, the furosine assay is useful in predicting RUP

Counteracting quasispecies adaptability: extinction of a ribavirin-resistant virus mutant by an alternative mutagenic treatment.

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Celia Perales

Full Text Available BACKGROUND: Lethal mutagenesis, or virus extinction promoted by mutagen-induced elevation of mutation rates of viruses, may meet with the problem of selection of mutagen-resistant variants, as extensively documented for standard, non-mutagenic antiviral inhibitors. Previously, we characterized a mutant of foot-and-mouth disease virus that included in its RNA-dependent RNA polymerase replacement M296I that decreased the sensitivity of the virus to the mutagenic nucleoside analogue ribavirin. METHODOLOGY AND PRINCIPAL FINDINGS: Replacement M296I in the viral polymerase impedes the extinction of the mutant foot-and-mouth disease virus by elevated concentrations of ribavirin. In contrast, wild type virus was extinguished by the same ribavirin treatment and, interestingly, no mutants resistant to ribavirin were selected from the wild type populations. Decreases of infectivity and viral load of the ribavirin-resistant M296I mutant were attained with a combination of the mutagen 5-fluorouracil and the non-mutagenic inhibitor guanidine hydrocloride. However, extinction was achieved with a sequential treatment, first with ribavirin, and then with a minimal dose of 5-fluorouracil in combination with guanidine hydrochloride. Both, wild type and ribavirin-resistant mutant M296I exhibited equal sensitivity to this combination, indicating that replacement M296I in the polymerase did not confer a significant cross-resistance to 5-fluorouracil. We discuss these results in relation to antiviral designs based on lethal mutagenesis. CONCLUSIONS: (i When dominant in the population, a mutation that confers partial resistance to a mutagenic agent can jeopardize virus extinction by elevated doses of the same mutagen. (ii A wild type virus, subjected to identical high mutagenic treatment, need not select a mutagen-resistant variant, and the population can be extinguished. (iii Extinction of the mutagen-resistant variant can be achieved by a sequential treatment of a

How the RNA isolation method can affect microRNA microarray results

DEFF Research Database (Denmark)

Podolska, Agnieszka; Kaczkowski, Bogumil; Litman, Thomas

2011-01-01

RNA microarray analysis on porcine brain tissue. One method is a phenol-guanidine isothiocyanate-based procedure that permits isolation of total RNA. The second method, miRVana™ microRNA isolation, is column based and recovers the small RNA fraction alone. We found that microarray analyses give different results...... that depend on the RNA fraction used, in particular because some microRNAs appear very sensitive to the RNA isolation method. We conclude that precautions need to be taken when comparing microarray studies based on RNA isolated with different methods.......The quality of RNA is crucial in gene expression experiments. RNA degradation interferes in the measurement of gene expression, and in this context, microRNA quantification can lead to an incorrect estimation. In the present study, two different RNA isolation methods were used to perform micro...

N-Guanidino Derivatives of 1,5-Dideoxy-1,5-imino-d-xylitol are Potent, Selective, and Stable Inhibitors of β-Glucocerebrosidase.

Science.gov (United States)

Sevšek, Alen; Šrot, Luka; Rihter, Jakob; Čelan, Maša; van Ufford, Linda Quarles; Moret, Ed E; Martin, Nathaniel I; Pieters, Roland J

2017-04-06

A series of lipidated guanidino and urea derivatives of 1,5-dideoxy-1,5-imino-d-xylitol were prepared from d-xylose using a concise synthetic protocol. Inhibition assays with a panel of glycosidases revealed that the guanidino analogues display potent inhibition against human recombinant β-glucocerebrosidase with IC 50 values in the low nanomolar range. Related urea analogues of 1,5-dideoxy-1,5-imino-d-xylitol were also synthesized and evaluated in the same fashion and found to be selective for β-galactosidase from bovine liver. No inhibition of human recombinant β-glucocerebrosidase was observed for the urea analogues. Computational studies provided insight into the potent activity of analogues bearing the substituted guanidine moiety in the inhibition of lysosomal glucocerebrosidase (GBA). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Runoff and degradation of aerially applied dinotefuran in paddy fields and river.

Science.gov (United States)

Yokoyama, Sayako; Ito, Masataka; Nagasawa, Shunsuke; Morohashi, Masayuki; Ohno, Masaki; Todate, Yukitaka; Kose, Tomohiro; Kawata, Kuniaki

2015-06-01

Variation, run-off and degradation characteristics of the insecticide dinotefuran, (EZ)-(RS)-1-methyl-2-nitro-3-(tetrahydro-3-furyl-methyl)guanidine, in water and soil from two paddy fields after aerial application was investigated as well as in river water. Maximum concentrations of dinotefuran were 290 and 720 µg/L in the two paddy waters, 25 and 28 µg/kg dry in the two paddy soils, and 10 µg/L in the river water. Runoff ratios of dinotefuran from the paddy fields were calculated as 14%-41%. Mean half-lives of dinotefuran were 5.4 days in the paddy water and 12 days in the paddy soil. Results obtained in this study are important for the evaluation of the actual behavior of dinotefuran in paddy fields and rivers.

[Changes in the expression of salivary gland genes in Ixodes persulcatus (Ixodidae) depending on the stage of tick feeding].

Science.gov (United States)

Shtannikov, A V; Perovskaia, O N; Reshetniak, T V; Repolovskaia, T V; Panfertsev, E A; Sergeeva, E E; Gutova, V P; Vasil'eva, I S; Ershova, A S; Prilipov, A G; Biketov, S F; Zeidner, N

2009-01-01

By using the guanidine-isothiocyanate test, the authors isolated a summary RNA preparation from Ixodes persulcatus salivary gland extracts. Activity products of the genes responsible for the expression of some salivary proteins were first identified using the RT-PCR. It has been shown that, firstly, I. persulcatus synthesizes at least 3 transcripts homologous to the respective salivary components of the related species I. scapularis, the translation product of which is likely to be immunodominant antigens; secondly, the number of each of these transcripts, as in I. scapularis, depends on the stage of tick feeding. The changes in the expression of each transcript are specific: monotonously increasing changes in Salp 17 and cyclic ones in Salp 16, and synthesis, only when the ticks are fully ingested, in Salp 25.

Photolabile ruthenium complexes to cage and release a highly cytotoxic anticancer agent.

Science.gov (United States)

Wei, Jianhua; Renfrew, Anna K

2018-02-01

CHS-828 (N-(6-(4-chlorophenoxy)hexyl)-N'-cyano-N″-4-pyridyl guanidine) is an anticancer agent with low bioavailability and high systemic toxicity. Here we present an approach to improve the therapeutic profile of the drug using photolabile ruthenium complexes to generate light-activated prodrugs of CHS-828. Both prodrug complexes are stable in the dark but release CHS-828 when irradiated with visible light. The complexes are water-soluble and accumulate in tumour cells in very high concentrations, predominantly in the mitochondria. Both prodrug complexes are significantly less cyototoxic than free CHS-828 in the dark but their toxicity increases up to 10-fold in combination with visible light. The cellular responses to light treatment are consistent with release of the cytotoxic CHS-828 ligand. Copyright © 2017 Elsevier Inc. All rights reserved.

2-Benzylsulfanyl-N-(1,3-dimethylimidazolidin-2-ylideneaniline

Directory of Open Access Journals (Sweden)

Ulrich Flörke

2013-04-01

Full Text Available The molecular structure of the title compound, C18H21N3S, shows a twisted conformation with a dihedral angle of 67.45 (4° between the aromatic ring planes and an N—C—C—S torsion angle of −5.01 (13°. The imidazolidine ring and the aniline moiety make a dihedral angle of 56.03 (4° and the asscociated C—N—C angle is 125.71 (10°. The guanidine-like C=N double bond is clearly localized, with a bond length of 1.2879 (14 Å. The C—S—C angle is 102.12 (5° and the S—C(aromatic and S—C bond lengths are 1.7643 (11 and 1.8159 (12 Å.

Iridium- and Ruthenium-Catalyzed N-alkylation of Amines with Alcohols and Amines

DEFF Research Database (Denmark)

Lorentz-Petersen, Linda Luise Reeh

-helical propensity. Hereby, it was believed that more stable proteins would be obtained. Folding of the mutants was studied in terms of thermodynamics and kinetics by guanidine hydrochloride denaturation monitored by fluorescence. The results were unfortunately unreliable due to errors in the spectrofluorometer....... in the reaction, as ethyleneglycol and 1,2-ethylenediamine failed to produce piperazine. Introduction of a C-substituent on one or both of the starting materials gave Csubstituted piperazines in high yields. Synthesis of N-benzylpiperazine from ethyleneglycol and N-benzylethylenediamine was also successful. Self...... experiments were conducted and emphasized the importance of the Voigt reaction in the formation of the product. Protein folding During an external stay at The Scripps Research Institute, San Diego, California, USA, folding of the well-known protein CI2 was studied. Several mutants were synthetically prepared...

Results of Analyses of the Next Generation Solvent for Parsons

International Nuclear Information System (INIS)

Peters, T.; Washington, A.; Fink, S.

2012-01-01

Savannah River National Laboratory (SRNL) prepared a nominal 150 gallon batch of Next Generation Solvent (NGS) for Parsons. This material was then analyzed and tested for cesium mass transfer efficiency. The bulk of the results indicate that the solvent is qualified as acceptable for use in the upcoming pilot-scale testing at Parsons Technology Center. This report describes the analysis and testing of a batch of Next Generation Solvent (NGS) prepared in support of pilot-scale testing in the Parsons Technology Center. A total of ∼150 gallons of NGS solvent was prepared in late November of 2011. Details for the work are contained in a controlled laboratory notebook. Analysis of the Parsons NGS solvent indicates that the material is acceptable for use. SRNL is continuing to improve the analytical method for the guanidine.

Recommendation for KIT-formulation of radioiodinated [{sup *}I] meta-iodo benzyl guanidine (M*IBG). Vol. 3.

Energy Technology Data Exchange (ETDEWEB)

El-shaboury, G; El-Kolaly, M T; Raieh, M; El-Bayoumy, S [Radioisotope Production and Labelled Compounds Department, Cairo (Egypt); Zakareia, N [Chemistry of Nuclear Fuel Department, Hot laboratories Center, Atomic Energy Authority, Cairo (Egypt)

1996-03-01

A recommended simple technique for preparation of radioiodinated [{sup *}I{sup -}] meta - iodobenzylguanidine (M{sup *} IBG) is presented. The technique is based on a schematic procedure for the synthesis of inactive M IBG using meta -iodo benzoic as substrate, results into a chemical yield of 80% as pure as M IBG 0.5 substrate, then recrystallized from water - ethyl alcohol as crystalline powder of M.P. 165 Degree C - 167 degree C. The radioiodination process is performed through an isotropic exchange reaction between the inactive M IBG and radioiodine as iodine ion ({sup *}I{sup -}) in 0.2 M acetate buffer pH 4.2 - 4.25 at 100 degree C within 30 min in the presence of metal as exchange catalyst. Following these processes, the reaction solution is allowed for purification by passing it through an AgCl - impregnated filter to remove the unreacted radioiodine as Ag{sup *}I (5%). According of these results and reaction conditions it was possible to develop a technology for the radiopharmaceutical production of radioiodinated M{sup *} IBG using the currently used short - lived radioiodine nuclides by a simple kit like - type technique, where the radiochemical yield % is 95 - 99% as pure as M{sup *} IBG. 5 figs., 3 tabs.

123I-meta-iodo-benzyl-guanidine myocardial scintigraphy and congestive heart failure: current data and perspective

International Nuclear Information System (INIS)

Agostini, D.; Darlas, Y.; Quennelle, F.; Bouvard, G.; Scanu, P.; Grollier, G.; Potier, J.C.; Babatasi, G.; Belin, A.

1997-01-01

Congestive heart failure is often associated with an impairment of the sympathetic nervous system, i.e., global hyperactivity and regional impairment of the adrenergic system. Cardiac 123 I-MIBG scintigraphy is a radionuclide technique which can explore the presynaptic adrenergic function. Myocardial MIBG fixation is decreased in congestive heart failure, reflecting a reduction of norepinephrine uptake by the myocardial presynaptic nerve endings. The impairment of presynaptic function occurs early in the disease and is actually involved in the pathogenesis of cardiac failure. Cardiac MIBG scintigraphy is a useful tool to explore the myocardial adrenergic stores in patients with congestive heart failure. It could be proposed in patients with severe ventricular dysfunction in order to assist physicians in setting-up the timing of heart transplantation. (authors)

Use of (S)-trans-gamma-monocyclofarnesol as a useful chiral building block for the stereoselective synthesis of diterpenic natural products.

Science.gov (United States)

Serra, Stefano; Cominetti, Alessandra A; Lissoni, Veronica

2014-03-01

A comprehensive study of the exploitation of (S)-trans-gamma-monocyclofarnesol as a useful chiral building block for the stereoselective synthesis of natural diterpene derivatives is here described. The farnesol derivative (+)-1 was used as starting material in the preparation of the diterpenes (S)-dehydroambliol-A and (S)-trixagol, as well as for the syntheses of the dinorditerpene (S)-dinortrixagone and of the guanidine-interrupted terpenoid (S)-dotofide. Key steps of the presented syntheses were the cross-coupling between an allyl acetate and a Grignard reagent, the Wittig reaction, the selective preparation ofa diacylguanidine derivative and the alkylation of a sulfone derivative, followed by the reductive removal of the same functional group. It is worth noting that the natural products (+)-8, (+)-12 and (+)-15 were prepared stereoselectively for the first time, thus allowing the unambiguous assignment of their absolute configuration.

Synthesis and characterization of arginine-NIPAAm hybrid hydrogel as wound dressing: In vitro and in vivo study.

Science.gov (United States)

Wu, De-Qun; Zhu, Jie; Han, Hua; Zhang, Jun-Zhi; Wu, Fei-Fei; Qin, Xiao-Hong; Yu, Jian-Yong

2018-01-01

A multi-functional hybrid hydrogel P(M-Arg/NIPAAm) with temperature response, anti-protein adsorption and antibacterial properties was prepared and applied as wound dressing. The hydrogel was carried out by free radical copolymerization of methacrylate arginine (M-Arg) and N-isopropyl acrylamide (NIPAAm) monomers using N,N'-methylene bisacrylamide as a crosslinker, and ammonium persulfate/N,N,N', N'-tetramethylethylenediamine as the redox initiator. To endow the antimicrobial property, chlorhexidine diacetate (CHX) was preloaded into the hydrogel and polyhexamethylene guanidine phosphate (PHMG) was grafted on the hydrogel surface, respectively. The antimicrobial property of two series of hydrogels was evaluated and compared. The successful synthesis of M-Arg, PHMG and hydrogels was proved by 13 C NMR, 1 H NMR and FTIR spectroscopy. The hydrogel morphology characterized by scanning electron microscopy confirmed that the homogeneous porous and interconnected structures of the hydrogels. The swelling, protein adsorption property, in vitro release of CHX, antimicrobial assessment, cell viability as well as in vivo wound healing in a mouse model were studied. The results showed the nontoxicity and antimicrobial P(M-Arg/NIPAAm) hydrogel accelerated the full-thickness wound healing process and had the potential application in wound dressing. Despite the zwitterionic characteristic and biocompatible property of arginine based hydrogels, the brittle behavior and non-transparency still remain as a significant problem for wound dressing. Furthermore promoting the antibacterial property of the zwitterionic hydrogel is also necessary to prevent the bacterial colonization and subsequent wound infection. Therefore, we created a hybrid hydrogel combined methacrylate arginine (M-Arg) and N-isopropyl acrylamide (NIPAAm). NIPAAm improves transparency and mechanical property as well as acts as a temperature-response drug release system. Additionally, chlorhexidine (CHX) was preloaded

Quantification of inhaled aerosol particles composed of toxic household disinfectant using radioanalytical method.

Science.gov (United States)

Shim, Ha Eun; Lee, Jae Young; Lee, Chang Heon; Mushtaq, Sajid; Song, Ha Yeon; Song, Lee; Choi, Seong-Jin; Lee, Kyuhong; Jeon, Jongho

2018-05-25

To assess the risk posed by a toxic chemical to human health, it is essential to quantify its uptake in a living subject. This study aims to investigate the biological distribution of inhaled polyhexamethylene guanidine (PHMG) aerosol particle, which is known to cause severe pulmonary damage. By labeling with indium-111 ( 111 In), we quantified the uptake of PHMG for up to 7 days after inhalation exposure in rats. The data demonstrate that PHMG is only slowly cleared, with approximately 74% of inhaled particles persisting in the lungs after 168 h. Approximately 5.3% of inhaled particles were also translocated to the liver after 168 h, although the level of redistribution to other tissues, including the kidneys and spleen, was minimal. These observations suggest that large uptake and slow clearance may underlie the fatal inhalation toxicity of PHMG in humans. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cardiac 123I-MIBG uptake in de novo Brazilian patients with Parkinson's disease without clinically defined dysautonomia

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Marco Antonio Araujo Leite

2014-06-01

Full Text Available Myocardial scintigraphy with meta-iodo-benzyl-guanidine (123I cMIBG has been studied in Parkinson's disease (PD, especially in Asian countries, but not in Latin America. Most of these studies include individuals with PD associated to a defined dysautonomia. Our goal is to report the cardiac sympathetic neurotransmission in de novo Brazilian patients with sporadic PD, without clinically defined dysautonomia. We evaluated retrospectively a series of 21 consecutive cases with PD without symptoms or signs of dysautonomia assessed by the standard bedside tests. This number was reduced to 14 with the application of exclusion criteria. 123I cMIBG SPECT up-take was low or absent in all of them and the heart/mediastinum ratio was low in 12 of 14. We concluded that 123I cMIBG has been able to identify cardiac sympathetic neurotransmission disorder in Brazilian de novo PD patients without clinically defined dysautonomia.

An expeditious and green synthesis of new enaminones and study their chemical reactivity toward some different amines and binucleophiles under environmentally friendly conditions

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Khadijah M. Al-Zaydi

2017-05-01

Full Text Available The condensation reaction of 3-heteroaromatic-3-oxopropanenitriles 3, 4 and 7 with dimethylformamide–dimethylacetal (DMF–DMA gave the corresponding enaminones 8, 9 and 10, respectively. Nucleophilic substitution of 8 and 9 with different amines resulted in a new derivatives of enaminones 11–18. The reactivity of enaminones 8 and 9 toward some nitrogen nucleophiles was investigated with a view to synthesize new heterocyclic systems. Thus, treatment of compounds 8 and 9 with phenylhydrazine afforded the pyrazole derivatives 19 and 20, respectively. On the other hand, reacting 8 and 9 with guanidine gave the pyrimidines 21 and 22, respectively. Treatment of compound 9 with hydroxylamine hydrochloride afforded the aminoisoxazoles 23. The foregoing reactions were carried out with conventional heating and under green conditions [ultrasound (US irradiations or ionic liquids (ILs] and a comparative study was employed. All the new structures are fully characterized.

Separation of ions in acidic solution by capillary electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Thornton, Michelle [Iowa State Univ., Ames, IA (United States)

1997-10-08

Capillary electrophoresis (CE) is an effective method for separating ionic species according to differences in their electrophoretic mobilities. CE separations of amino acids by direct detection are difficult due to their similar electrophoretic mobilities and low absorbances. However, native amino acids can be separated by CE as cations at a low pH by adding an alkanesulfonic acid to the electrolyte carrier which imparts selectivity to the system. Derivatization is unnecessary when direct UV detection is used at 185 nm. Simultaneous speciation of metal cations such as vanadium (IV) and vanadium (V) can easily be performed without complexation prior to analysis. An indirect UV detection scheme for acidic conditions was also developed using guanidine as the background carrier electrolyte (BCE) for the indirect detection of metal cations. Three chapters have been removed for separate processing. This report contains introductory material, references, and general conclusions. 80 refs.

Expression, purification, and refolding of active recombinant human E-selectin lectin and EGF domains in Escherichia coli.

Science.gov (United States)

Kawano, Susumu; Iyaguchi, Daisuke; Okada, Chiaki; Sasaki, Yusuke; Toyota, Eiko

2013-06-01

Attempts to obtain active E-selectin from Escherichia coli (E. coli) have not yet been successful. In this study, we succeeded in expressing the recombinant lectin and epidermal growth factor domain fragments of human E-selectin (rh-ESLE) in E. coli on a large-scale. The rh-ESLE protein was expressed as an inactive form in the inclusion bodies. The inactive form of rh-ESLE was denatured and solubilized by 6 M guanidine hydrochloride and then purified by Ni(2+) affinity chromatography under denaturing conditions. Denatured rh-ESLE was then refolded by a rapid-dilution method using a large amount of refolding buffer, which contained arginine and cysteine/cystine. The refolded rh-ESLE showed binding affinity for sLe(X) (K(d) = 321 nM, B(max) = 1.9 pmol/μg protein). This result suggests that the refolded rh-ESLE recovered its native and functional structure.

N,N,N′-Trimethyl-N′′-(4-nitrophenyl-N′-phenylguanidine

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Ioannis Tiritiris

2014-05-01

Full Text Available The C—N bond lengths in the guanidine unit of the title compound, C16H18N4O2, are 1.298 (2, 1.353 (2 and 1.401 (3 Å, indicating double- and single-bond character. The N—C—N angles are 115.81 (16, 118.90 (18 and 125.16 (18°, showing a deviation of the CN3 plane from an ideal trigonal–planar geometry. In the crystal, C—H...O hydrogen bonds are observed between the methyl- and aromatic-H atoms and nitro-O atoms. One H atom of the phenyl ring and of the NMe2 group associate with the O atoms of the nitro group, giving chains along the a- and b-axis directions. Cross-linking of these two chains results in a two-dimensional network along bc.

Metabolomic study of lipids in serum for biomarker discovery in Alzheimer's disease using direct infusion mass spectrometry.

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González-Domínguez, R; García-Barrera, T; Gómez-Ariza, J L

2014-09-01

In this study, we demonstrated the potential of direct infusion mass spectrometry for the lipidomic characterization of Alzheimer's disease. Serum samples were extracted for lipids recovery, and directly analyzed using an electrospray source. Metabolomic fingerprints were subjected to multivariate analysis in order to discriminate between groups of patients and healthy controls, and then some key-compounds were identified as possible markers of Alzheimer's disease. Major differences were found in lipids, although some low molecular weight metabolites also showed significant changes. Thus, important metabolic pathways involved in neurodegeneration could be studied on the basis of these perturbations, such as membrane breakdown (phospholipids and diacylglycerols), oxidative stress (prostaglandins, imidazole and histidine), alterations in neurotransmission systems (oleamide and putrescine) and hyperammonaemia (guanidine and arginine). Moreover, it is noteworthy that some of these potential biomarkers have not been previously described for Alzheimer's disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Nitrogen-doped titanium dioxide photocatalysts for visible response prepared by using organic compounds

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Yoshio Nosaka, Masami Matsushita, Junichi Nishino and Atsuko Y. Nosaka

2005-01-01

Full Text Available In order to utilize visible light in photocatalytic reactions, nitrogen atoms were doped in commercially available photocatalytic TiO2 powders by using an organic compound such as urea and guanidine. Analysis by X-ray photoelectron spectroscopy (XPS indicated that N atoms were incorporated into two different sites of the bulk phase of TiO2. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These N-doped TiO2 powders exhibited photocatalytic activity for the decomposition of 2-propanol in aqueous solution under visible light irradiation. The photocatalytic activity increased with the decrease of doped N atoms in O site, while decreased with decrease of the other sites. Degradation of photocatalytic activity based on the release of nitrogen atoms was observed for the reaction in the aqueous suspension system.

Silicon microring refractometric sensor for atmospheric CO(2) gas monitoring.

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Mi, Guangcan; Horvath, Cameron; Aktary, Mirwais; Van, Vien

2016-01-25

We report a silicon photonic refractometric CO(2) gas sensor operating at room temperature and capable of detecting CO(2) gas at atmospheric concentrations. The sensor uses a novel functional material layer based on a guanidine polymer derivative, which is shown to exhibit reversible refractive index change upon absorption and release of CO(2) gas molecules, and does not require the presence of humidity to operate. By functionalizing a silicon microring resonator with a thin layer of the polymer, we could detect CO(2) gas concentrations in the 0-500ppm range with a sensitivity of 6 × 10(-9) RIU/ppm and a detection limit of 20ppm. The microring transducer provides a potential integrated solution in the development of low-cost and compact CO(2) sensors that can be deployed as part of a sensor network for accurate environmental monitoring of greenhouse gases.

Preoperative Embolization Reduces the Risk of Cathecolamines Release at the Time of Surgical Excision of Large Pelvic Extra-Adrenal Sympathetic Paraganglioma

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Nicola Di Daniele

2012-01-01

Full Text Available A 30-year-old woman with severe hypertension was admitted to the hospital with a history of headache, palpitations, and diaphoresis following sexual intercourse. Twenty-four hour urinary excretion of free catecholamines and metabolites was markedly increased as was serum chromogranin A. Computed tomography scan revealed a large mass in the left adnex site and magnetic resonance imaging confirmed the computer tomography finding, suggesting the presence of extra-adrenal sympathetic paraganglioma. I-metaiodobenzyl guanidine scintigram revealed an increased uptake in the same area. Transcatheter arterial embolization of the mass resulted in marked decreases in blood pressure and urinary excretion of free catecholamines and metabolites. Surgical excision of the mass was then accomplished without complication. Preoperative embolization is a useful and safe procedure which may reduce the risk of catecholamines release at the time of surgical excision in large pelvic extra-adrenal sympathetic paraganglioma.

Radiation exposure to parents nursing their child during treatment with 131-I-meta-iodobenzyl guanidine for neuroblastoma

International Nuclear Information System (INIS)

Marcuse, H.R.; Steen, J.v.d.; Maessen, H.J.M.; Hoefnagel, C.A.; Voute, P.A.

1986-01-01

After 22 treatments involving eight patients the radiation dose equivalent received by parents is described. Patients received 1.5 - 5.5 GBq 131 I as MIBG by 1 - 24 hours infusion. Selection for therapy was made after a diagnostic examination of MIBG uptake with quantities less than 40 MBq. The decision for treatment was based on estimations of the radiation dose delivered to the tumor and to normal organs and the general condition of the patient. The hospital is licenced to discharge patients if a number of conditions concerning the administered radioactivity are satisfied. It is shown that the dose equivalent to the parent can be kept to an acceptable level of approximately 1 mSv per treatment. This dose equivalent is mainly due to external radiation since blocking the parent's thyroid leads to negligible dose equivalent from internal contamination. (Author)

Radiation exposure to parents nursing their child during treatment with 131-I-meta-iodobenzyl guanidine for neuroblastoma

International Nuclear Information System (INIS)

Marcuse, H.R.; van der Steen, J.; Maessen, H.J.M.; Hoefnagel, C.A.; Voute, P.A.

1986-01-01

After 22 treatments involving eight patients the radiation dose equivalent received by parents is described. Patients received 1.5-5.5 GBq I-131 as MIBG by 1-24 hours infusion. Selection for therapy was made after a diagnostic examination of MIBG uptake with quantities less than 40 Mbq. The decision for treatment was based on estimations of the radiation dose delivered to the tumor and to normal organs and the general condition of the patient. The hospital is licensed to discharge patients if a number of conditions concerning the administered radioactivity are satisfied. It is shown that the dose equivalent to the parent can be kept to an acceptable level of approximately 1 mSv per treatment. This dose equivalent is mainly due to external radiation since blocking the parent's thyroid leads to negligible dose equivalent from internal contamination. 2 references, 2 figures, 1 table

Reactivity of Tin(II) Guanidinate with 1,2- and 1,3-Diones: Oxidative Cycloaddition or Ligand Substitution ?

Czech Academy of Sciences Publication Activity Database

Chlupatý, T.; Růžičková, Z.; Horáček, Michal; Merna, J.; Alonso, M.; de Proft, F.; Růžička, A.

2015-01-01

Roč. 34, č. 11 (2015), s. 2202-2211 ISSN 0276-7333 Institutional support: RVO:61388955 Keywords : DENSITY-FUNCTIONAL THEORY * CRYSTAL-STRUCTURE * ADDITION- REACTION S Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.186, year: 2015

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

Science.gov (United States)

Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

2015-04-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/μg and 1.72(14) nL/μg were found for Milli-Q water and lysis-binding buffer, respectively.

Tubular transport and metabolism of cimetidine in chicken kidneys

International Nuclear Information System (INIS)

Rennick, B.; Ziemniak, J.; Smith, I.; Taylor, M.; Acara, M.

1984-01-01

Renal tubular transport and renal metabolism of [ 14 C]cimetidine (CIM) were investigated by unilateral infusion into the renal portal circulation in chickens (Sperber technique). [ 14 C]CIM was actively transported at a rate 88% that of simultaneously infused p-aminohippuric acid, and its transport was saturable. The following organic cations competitively inhibited the tubular transport of [ 14 C]CIM with decreasing potency: CIM, ranitidine, thiamine, procainamide, guanidine and choline. CIM inhibited the transport of [ 14 C]thiamine, [ 14 C]amiloride and [ 14 C]tetraethylammonium. During CIM infusion, two renal metabolites, CIM sulfoxide and hydroxymethylcimetidine, were found in urine. When CIM sulfoxide was infused, its transport efficiency was 32% and not saturable. CIM sulfoxide did ot inhibit the simultaneous renal tubular transport of p-aminohippuric acid or tetraethylammonium. CIM is transported by the organic cation transport system and the kidney metabolizes CIM. Transport of CIM and other cationic drugs could produce a drug interaction to alter drug excretion

Contributions of molecular size, charge distribution, and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates.

Science.gov (United States)

Sun, Na; Cui, Pengbo; Jin, Ziqi; Wu, Haitao; Wang, Yixing; Lin, Songyi

2017-09-01

This study investigated the contributions of molecular size, charge distribution and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates (SCOHs), and further explored their iron-binding sites. It was demonstrated that enzyme type and degree of hydrolysis (DH) significantly influenced the iron-binding capacity of the SCOHs. The SCOHs produced by alcalase at a DH of 25.9% possessed the highest iron-binding capacity at 92.1%. As the hydrolysis time increased, the molecular size of the SCOHs decreased, the negative charges increased, and the hydrophilic amino acids were exposed to the surface, facilitating iron binding. Furthermore, the Fourier transform infrared spectra, combined with amino acid composition analysis, revealed that iron bound to the SCOHs primarily through interactions with carboxyl oxygen of Asp, guanidine nitrogen of Arg or nitrogen atoms in imidazole group of His. The formed SCOHs-iron complexes exhibited a fold and crystal structure with spherical particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photoinduced Cross-Linking of Dynamic Poly(disulfide) Films via Thiol Oxidative Coupling.

Science.gov (United States)

Feillée, Noémi; Chemtob, Abraham; Ley, Christian; Croutxé-Barghorn, Céline; Allonas, Xavier; Ponche, Arnaud; Le Nouen, Didier; Majjad, Hicham; Jacomine, Léandro

2016-01-01

Initially developed as an elastomer with an excellent record of barrier and chemical resistance properties, poly(disulfide) has experienced a revival linked to the dynamic nature of the S-S covalent bond. A novel photobase-catalyzed oxidative polymerization of multifunctional thiols to poly(disulfide) network is reported. Based solely on air oxidation, the single-step process is triggered by the photodecarboxylation of a xanthone acetic acid liberating a strong bicyclic guanidine base. Starting with a 1 μm thick film based on trithiol poly(ethylene oxide) oligomer, the UV-mediated oxidation of thiols to disulfides occurs in a matter of minutes both selectively, i.e., without overoxidation, and quantitatively as assessed by a range of spectroscopic techniques. Thiolate formation and film thickness determine the reaction rates and yield. Spatial control of the photopolymerization serves to generate robust micropatterns, while the reductive cleavage of S-S bridges allows the recycling of 40% of the initial thiol groups. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluctuating partially native-like topologies in the acid denatured ensemble of autolysis resistant HIV-1 protease.

Science.gov (United States)

Rout, Manoj Kumar; Hosur, Ramakrishna V

2009-02-01

Folding, in-vivo, starts from a denatured state and thus the nature of the denatured state would play an important role in directing the folding of a protein. We report here NMR characterization of the acid-denatured state of a mutant of HIV-1 protease, designed to prevent autolysis (Q7K, L33I, L63I) and to prevent cysteine oxidation (C67A and C95A). Secondary chemical shifts, TALOS analysis of chemical shifts and (15)N relaxation data (R(1), R(2), NOE) coupled with AABUF and hydrophobicity calculations, suggest formation of hydrophobic clusters and possibility of some partially native-like topologies in the acid denatured state of the protease. The structural and dynamics characteristics of the acid denatured PR seem to be considerably different from those of the guanidine or urea denatured states of some variants of PR. These would have implications for the folding and auto-processing of the enzyme in-vivo.

Factors influencing the cardiac MIBG accumulation

International Nuclear Information System (INIS)

Takatsu, Hisato; Fujiwara, Hisayoshi

1997-01-01

Following factors possibly influencing the cardiac MIBG accumulation were examined mainly in mice. 1. The specific activity of the MIBG (meta-iodo-benzyl guanidine) on the neuronal and non-neuronal fractions. 2. Motor restriction stress on MIBG accumulation and washout. 3. Loading and restriction of sodium chloride on the accumulation and effect of suppression of renin-angiotensin system. 4. Examinations in Dahl rats. 125I- or 131I-MIBG was intravenously administered to mice at 74 kBq. At 30 min or 4 hr after administration, mice were sacrificed and their left ventricles were dissected out for measurement of radioactivity in a liquid scintillation counter. Salt-sensitive and -resistant Dahl rats were given with 37 MBq of 123I-MIBG and cardiac radioactivity was measured externally for calculation of washout. Factors examined were found highly correlated with the accumulation of MIBG and measurement of its washout was considered useful for evaluating sympathetic activity. (K.H.)

An Expeditious and Greener Synthesis of 2-Aminoimidazoles in Deep Eutectic Solvents

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Martina Capua

2016-07-01

Full Text Available A high-yield one-pot two-step synthesis of 2-aminoimidazoles (2-AI, exploiting an under-air heterocyclodehydration process between α-chloroketones and guanidine derivatives, and using deep eutectic solvents (DESs as nonconventional, “green” and “innocent” reaction media, has been accomplished successfully. The combination of either glycerol or urea with choline chloride (ChCl proved to be effective for decreasing the reaction time to about 4–6 h in contrast to the 10–12 h usually required for the same reaction run in toxic and volatile organic solvents and under an argon atmosphere. In addition, the use of the ChCl–urea as a DES also enables the direct isolation of triaryl-substituted 2-AI derivatives by means of a simple work-up procedure consisting in filtration and crystallization, and allows the recycle of the DES mixture. A plausible mechanism highlighting the potential role played by hydrogen bonding catalysis has also been illustrated.

Proteoglycon synthesis by articular chondrocytes in agarose culture

International Nuclear Information System (INIS)

Sweet, M.B.E.; Grisillo, A.; Coehlo, A.; Schnitzler, C.M.

1987-01-01

Articular chondrocytes were isolated from knee joints of full-term bovine foetuses and grown in long-term agarose cultures. At intervals, cultures were labelled with 35 S-[sulphate] or D[6- 3 H] glucosamine. Newly synthesized proteoglycans were extracted with 4 M guanidine HCl and purified by isopycnic density gradient centrifugation or on DEAE cellulose in the presence of 8 M urea. Characterization of the proteoglycans revealed them to be identical in size to those present in the tissue and to be similarly capable of aggregation with hyaluronate. Newly synthesized chondroitin sulphate chains were identical in size, but newly synthesized keratan sulphate chains were somewhat larger than those present in the tissue. The newly synthesized proteoglycans were shown to contain the same range of O-linked oligosaccharides identified in proteoglycans of the Swarm rat chondrosarcoma. Cartilage-specific proteoglycan continued to be synthesized by the chondrocytes for up to 60 days; however, with time, proportionately more of a small non-aggregating proteoglycan appeared

HIV avidity index performance using a modified fourth-generation immunoassay to detect recent HIV infections.

Science.gov (United States)

Suligoi, Barbara; Regine, Vincenza; Raimondo, Mariangela; Rodella, Anna; Terlenghi, Luigina; Caruso, Arnaldo; Bagnarelli, Patrizia; Capobianchi, Maria Rosaria; Zanchetta, Nadia; Ghisetti, Valeria; Galli, Claudio

2017-10-26

Detecting recent HIV infections is important to evaluate incidence and monitor epidemic trends. We aimed to evaluate the diagnostic performance and accuracy of the avidity index (AI) for discriminating for recent HIV infections. We collected serum samples from HIV-1 positive individuals: A) with known date of infection (midpoint in time between last HIV-negative and first HIV-positive test); B) infected for >1 year. Samples were divided into two aliquots: one diluted with phosphate buffered saline (PBS) and the other with 1 M guanidine. Both aliquots were assayed by the Architect HIV Ag/Ab Combo 4th generation assay (Abbott). We compared AI found in recent (RI=HIV subtype had no impact on AI misclassifications. All individuals in group A reached the AI threshold of 0.80 within 24 months after seroconversion. The AI is an accurate serological marker for discriminating recent from established HIV infections and meets WHO requirements for HIV incidence assays.

A study of anti-inflammatory and analgesic activity of new 2,4,6-trisubstituted pyrimidines.

Science.gov (United States)

Yejella, Rajendra Prasad; Atla, Srinivasa Rao

2011-01-01

Chalcone derivatives (3a-m) were prepared by condensing 4-aminoacetophenone with various substituted aromatic and hetero aromatic aldehydes according to Claisen-Schmidt condensation. These chalcones, on reaction with guanidine hydrochloride under basic alcoholic conditions gave 2,4,6-trisubstituted pyrimidines (5a-m) in quantitative yields. All the newly synthesized pyrimidines were characterized by means of IR, ¹H- and ¹³C-NMR, Electron Ionization (EI)-mass and elemental analyses and screened for anti-inflammatory and analgesic activities by in vivo. 2-amino-4-(4-aminophenyl)-6-(2,4-dichlorophenyl)pyrimidine (5b) and 2-amino-4-(4-aminophenyl)-6-(3-bromophenyl) pyrimidine (5d) were found to be the most potent anti-inflammatory and analgesic activity compared with ibuprofen, reference standard. And also it was found that compound 5b identified as lead structure among all in both the activities. Pyrimidines which showed good anti-inflammatory activity also displayed better analgesic activity.

Microanalysis of oligosaccharide HS203 in beagle dog plasma by postcolumn fluorescence derivatization method.

Science.gov (United States)

Sun, Shumeng; Zhao, Xia; Li, Guangsheng; Yu, Guangli; Xing, Xiaoxu; Zeng, Yangyang; Wu, Jian; Wang, Jianing

2012-06-20

A rapid and sensitive postcolumn fluorescence derivatization method was developed for microanalysis of antidiabetic oligosaccharide HS203 in beagle dog plasma. After plasma protein was removed by a simple and fast ultrafiltration method, chromatographic separation was performed on an Asahipak GS-320 HQ column with a mobile phase of 50 mmol/L phosphate buffer (pH 6.7) and acetonitrile (83/17, v/v). The column effluent was monitored by fluorescence detection at 249 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as a postcolumn derivatizing reagent. A satisfactory resolution of the analyte was achieved and the limit of detection was found to be 4 ng (more sensitive than silver staining of HS203 in polyacrylamide gel electrophoresis). The method described above was successfully applied to a pharmacokinetic study of HS203 and to monitor blood glucose level simultaneously in beagle dog. It is also possible to be applied for microanalysis of other oligosaccharides in biological samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mimicking of Arginine by Functionalized N(ω)-Carbamoylated Arginine As a New Broadly Applicable Approach to Labeled Bioactive Peptides: High Affinity Angiotensin, Neuropeptide Y, Neuropeptide FF, and Neurotensin Receptor Ligands As Examples.

Science.gov (United States)

Keller, Max; Kuhn, Kilian K; Einsiedel, Jürgen; Hübner, Harald; Biselli, Sabrina; Mollereau, Catherine; Wifling, David; Svobodová, Jaroslava; Bernhardt, Günther; Cabrele, Chiara; Vanderheyden, Patrick M L; Gmeiner, Peter; Buschauer, Armin

2016-03-10

Derivatization of biologically active peptides by conjugation with fluorophores or radionuclide-bearing moieties is an effective and commonly used approach to prepare molecular tools and diagnostic agents. Whereas lysine, cysteine, and N-terminal amino acids have been mostly used for peptide conjugation, we describe a new, widely applicable approach to peptide conjugation based on the nonclassical bioisosteric replacement of the guanidine group in arginine by a functionalized carbamoylguanidine moiety. Four arginine-containing peptide receptor ligands (angiotensin II, neurotensin(8-13), an analogue of the C-terminal pentapeptide of neuropeptide Y, and a neuropeptide FF analogue) were subject of this proof-of-concept study. The N(ω)-carbamoylated arginines, bearing spacers with a terminal amino group, were incorporated into the peptides by standard Fmoc solid phase peptide synthesis. The synthesized chemically stable peptide derivatives showed high receptor affinities with Ki values in the low nanomolar range, even when bulky fluorophores had been attached. Two new tritiated tracers for angiotensin and neurotensin receptors are described.

Direct Aminolysis of Ethoxycarbonylmethyl 1,4-Dihydropyridine-3-carboxylates

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Brigita Vigante

2015-11-01

Full Text Available The ethoxycarbonylmethyl esters of 1,4-dihydropyridines were directly converted into carbamoylmethyl esters in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD in good to excellent yields under mild conditions. The use of TBD is crucial for the successful aminolysis of ethoxycarbonylmethyl ester of 1,4-dihydropyridines with secondary amines as without it the reaction does not proceed at all. The aminolysis reaction proceeded regioselectively, as the alkyl ester conjugated with the 1,4-dihydropyridine cycle was not involved in the reaction. Screening of other N-containing bases, such as triethylamine (TEA, pyridine, 4-(N,N-dimethylaminopyridine (DMAP, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 1,5-diazabicyclo[4.3.0]non-5-ene (DBN, imidazole, tetramethyl guanidine (TMG and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD as catalysts revealed no activity in the studied reaction.

Combinatorial Libraries As a Tool for the Discovery of Novel, Broad-Spectrum Antibacterial Agents Targeting the ESKAPE Pathogens.

Science.gov (United States)

Fleeman, Renee; LaVoi, Travis M; Santos, Radleigh G; Morales, Angela; Nefzi, Adel; Welmaker, Gregory S; Medina-Franco, José L; Giulianotti, Marc A; Houghten, Richard A; Shaw, Lindsey N

2015-04-23

Mixture based synthetic combinatorial libraries offer a tremendous enhancement for the rate of drug discovery, allowing the activity of millions of compounds to be assessed through the testing of exponentially fewer samples. In this study, we used a scaffold-ranking library to screen 37 different libraries for antibacterial activity against the ESKAPE pathogens. Each library contained between 10000 and 750000 structural analogues for a total of >6 million compounds. From this, we identified a bis-cyclic guanidine library that displayed strong antibacterial activity. A positional scanning library for these compounds was developed and used to identify the most effective functional groups at each variant position. Individual compounds were synthesized that were broadly active against all ESKAPE organisms at concentrations development of resistance, and displayed almost no toxicity when tested against human lung cells and erythrocytes. Using a murine model of peritonitis, we also demonstrate that these agents are highly efficacious in vivo.

Thermodynamics of mixed-ligand complex formation of mercury (II) ethylenediaminetetraacetate with amino acids in solution

Energy Technology Data Exchange (ETDEWEB)

Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Kozlovskii, Eugenii [Department of Inorganic and Analytic Chemistry, Ivanovo State University, Ermak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvei; Kumeev, Roman [Institute of Solution Chemistry, Ivanovo (Russian Federation)

2012-11-20

Highlights: Black-Right-Pointing-Pointer Stable mixed ligand complexes of HgEdta with amino acids at physiological pH value. Black-Right-Pointing-Pointer The thermodynamic and NMR data evident the ambidentate coordination mode of arginine. Black-Right-Pointing-Pointer Participation of the guanidinic group of Arg in coordination process. Black-Right-Pointing-Pointer Binuclear complexes (HgEdta){sub 2}L with the bridging function of amino acid. - Abstract: The mixed-ligand complex formation in the systems Hg{sup 2+} - Edta{sup 4-} - L{sup -}(L = Arg, Orn, Ser) has been studied by means of calorimetry, pH-potentiometry and NMR spectroscopy in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the HgEdtaL, HgEdtaHL and (HgEdta){sub 2}L complexes have been determined. The most probable coordination mode for the complexone and the amino acid in the mixed-ligand complexes was discussed.

Yersinia Virulence Depends on Mimicry of Host Rho-Family Nucleotide Dissociation Inhibitors

Energy Technology Data Exchange (ETDEWEB)

Prehna,G.; Ivanov, M.; Blisha, J.; Stebbins, C.

2006-01-01

Yersinia spp. cause gastroenteritis and the plague, representing historically devastating pathogens that are currently an important biodefense and antibiotic resistance concern. A critical virulence determinant is the Yersinia protein kinase A, or YpkA, a multidomain protein that disrupts the eukaryotic actin cytoskeleton. Here we solve the crystal structure of a YpkA-Rac1 complex and find that YpkA possesses a Rac1 binding domain that mimics host guanidine nucleotide dissociation inhibitors (GDIs) of the Rho GTPases. YpkA inhibits nucleotide exchange in Rac1 and RhoA, and mutations that disrupt the YpkA-GTPase interface abolish this activity in vitro and impair in vivo YpkA-induced cytoskeletal disruption. In cell culture experiments, the kinase and the GDI domains of YpkA act synergistically to promote cytoskeletal disruption, and a Y. pseudotuberculosis mutant lacking YpkA GDI activity shows attenuated virulence in a mouse infection assay. We conclude that virulence in Yersinia depends strongly upon mimicry of host GDI proteins by YpkA.

Heterocycles X V- one pot synthesis of indenyl pyrimidine- 2 - ones

International Nuclear Information System (INIS)

EL-Rayyes, R. N.

1997-01-01

Condensation of 1- indanone, aryl aldehydes (Ia-k) and urea revealed the formation of the corresponding dihydropyrimidinones (I Ia - k). these were acetaldeyde and brominated to give compounds (III) and (IV) respective l. Dehydrogenation of (II) gave the corresponding pyrimuidunones (V). The structures of the products (II - V) were substantiated by chemical and spectral methods. In a previous work, 1- indanone was reacted with guanidine to produce 2- amino - isopropylenediamine (1) . On the other hand, indenyl pyrimidine - 2- ones were previously prepared through a multi - step synthesis (2,3). The present investigation describes a one - pot synthesis of some new dihydropyrimidinones (I Ia - K). Thus 1- indanone and urea were condensed with aryl aldehydes (Ia - K) to produce the corresponding 4- aryl - 3,4- dihydro - 5 [H] - indenyl (1,2 -e) py rimidin - 2 (I H) ones (I Ia - K) (2,3). The structure of these products was substantiated by chemical and spectral methods as well as elemental analysis.(author). 11 refs., 3 table

Plant Defense Response to Fungal Pathogens (Activation of Host-Plasma Membrane H+-ATPase by Elicitor-Induced Enzyme Dephosphorylation).

Science.gov (United States)

Vera-Estrella, R.; Barkla, B. J.; Higgins, V. J.; Blumwald, E.

1994-01-01

Elicitor preparations containing the avr5 gene products from race 4 of Cladosporium fulvum and tomato (Lycopersicon esculentum L.) cells near isogenic for the resistance gene Cf5 were used to investigate events following the treatment of host plasma membranes with elicitor. A 4-fold increase in H+-ATPase activity, coincident with the acidification of the extracellular medium, was detected immediately after elicitor treatment. The elicitor-induced stimulation of the plasma membrane H+-ATPase was inhibited by okadaic acid but not by staurosporine, suggesting that protein dephosphorylation was required for increased H+-ATPase activity. This observation was confirmed by [gamma]-32P labeling and immunodetection of the plasma membrane H+-ATPase. Effects of guanidine nucleotide analogs and mastoparan on the ATPase activity suggested the role of GTP-binding proteins in mediating the putative elicitor-receptor binding, resulting in activation of a phosphatase(s), which in turn stimulates the plasma membrane H+-ATPase by dephosphorylation. PMID:12232073

Cationic surfactants for control of fresh- and saltwater mollusks in nuclear cooling systems

International Nuclear Information System (INIS)

Post, R.M.; Mallen, E.; Lehmann, F.

1991-01-01

One result of the release of the US Nuclear Regulatory Commission's Generic Letter 89-13, Service Water Problems Affecting Safety-Related Equipment, was the heightened awareness of the nuclear industry to the problems of macrofouling in heat exchange systems. The principal mollusk species that contribute to freshwater macrofouling problems are Asiatic Clam (southern United States) and Zebra Mussel (Great Lakes). The predominant saltwater fouling mollusks are the Blue Mussel (Pacific, northern Atlantic), Ribbed Mussel (southern Atlantic, Gulf Coast), and American Oyster (Atlantic, Gulf Coast). The nuclear community's awareness of macrofouling problems and the ineffectiveness of intermittent chlorination programs have led to the development of several chemical control technologies for eliminating macrofouling organism infestation. One technology that has proven effective for the control of macrofouling organisms is the periodic addition of a combination of two cationic charged surfactants, specifically, alkyldimethylbenzylammonium chloride (QUAT) and dodecyl guanidine hydrochloride (DGH). Experience with the cationic surfactants at several nuclear power plants is reported

The effect of an insulin releasing agent, BTS 67582, on advanced glycation end product formation in vitro.

Science.gov (United States)

Simpson, A E; Jones, R B

1999-01-01

BTS 67582 (1,1-dimethyl-2-(2-morpholinophenyl) guanidine fumarate) is an insulin-releasing agent currently in phase II clinical trials. Its effect on advanced glycation end product (AGE) formation was measured in the BSA/D-glucose and L-lysine/glucose-6-phosphate assay systems and Amadori product formation was measured in the BSA/D-glucose assay system, following a 3 week incubation period. In the BSA/D-glucose assay system, 200 mM BTS 67582 caused an approximate 70% inhibition in AGE formation (pBTS 67582 and 200 mM aminoguanidine-HCl retarded Amadori product formation by 88% (pBTS 67582 at 20 mM and 2 mM was shown to inhibit Amadori product formation by 67% and 57%, respectively, (pBTS 67582 and 200 mM aminoguanidine-HCl were shown to inhibit AGE formation by about 70% and 96% (p<0.001), respectively. Tolbutamide (200 microM) and glibenclamide (100 microM) had no significant effect on AGE formation.

Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

Science.gov (United States)

Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

2008-01-01

AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

Fatty Acid Biosynthesis IX

DEFF Research Database (Denmark)

Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

1972-01-01

# 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

Short-lived radionuclides program at the University of Michigan

International Nuclear Information System (INIS)

Wieland, D.M.

1985-01-01

The University of Michigan Nuclear Medicine Research Program, from instrumentation design through radiopharmaceutical development to clinical evaluation, is heavily dependent on the availability and use of iodine-123. Research activities at the University of Michigan can be divided into four major areas: instrumentation, radiochemistry, radiopharmaceutical development, and clinical evaluation. In the first category a new single-photon ring tomograph (SPRINT) has been built and is undergoing performance testing. SPRINT has been designed specifically for brain imaging with 123 I-labeled agents. In the area of radiochemistry, a simple radioiodide exchange technique has been developed for the rapid synthesis of 123 I-labeled aromatic compounds. In the radiopharmaceutical arena, a new agent, 123 I-meta-iodobenzyl-guanidine (MIBG), has been developed - the result of an extensive structure-distribution-relationship study. This radiopharmaceutical, a storage analog of norepinephrine, images organs with rich sympathetic innervation such as the heart and spleen. In the Nuclear Medicine Clinic three 123 I-labeled radiopharmaceuticals are undergoing evaluation

Enhanced Production of Vitamin K2 from Bacillus subtilis (nattoby Mutation and Optimization of the Fermentation Medium

Directory of Open Access Journals (Sweden)

Junying Song

2014-08-01

Full Text Available The aim of this study was to enhance the production of vitamin K2 by using N-methyl-N-nitro-N-nitroso-guanidine (NTG and low energy ion beam implantation and optimizing the fermentation medium. Mutation resulted in 1.66-fold higher production of vitamin K2 than that of the parentl strain. The production by the mutant BN-P15-11-1was increased 55% and reached 3.593±0.107 mg/L by using the Plackett-Burman and Box-Behnken designs to optimize the fermentation medium. The optimal fermentation culture medium was composed of (g/L glycerol 69.6, sucrose 34.5, K2HPO4 4.0, peptone 20, yeast extract 25 and fermented at 37 °C and 150 rpm for 72 h. The results showed that the NTG and low energy ion beam implantation mutations and optimizing fermentation medium were effective methods to enhance vitamin K2production.

The concentration, gene expression, and spatial distribution of aggrecan in canine articular cartilage, meniscus, and anterior and posterior cruciate ligaments: a new molecular distinction between hyaline cartilage and fibrocartilage in the knee joint.

Science.gov (United States)

Valiyaveettil, Manojkumar; Mort, John S; McDevitt, Cahir A

2005-01-01

The concentration, spatial distribution, and gene expression of aggrecan in meniscus, articular cartilage, and the anterior and posterior cruciate ligaments (ACL and PCL) was determined in the knee joints of five mature dogs. An anti-serum against peptide sequences specific to the G1 domain of aggrecan was employed in competitive-inhibition ELISA of guanidine HCl extracts and immunofluorescence microscopy. Gene expression was determined by Taqman real-time PCR. The concentration of aggrecan in articular cartilage (240.1 +/- 32 nMol/g dry weight) was higher than that in meniscus (medial meniscus: 33.4 +/- 4.3 nMol/g) and ligaments (ACL: 6.8 +/- 0.9 nMol/g). Aggrecan was more concentrated in the inner than the outer zone of the meniscus. Aggrecan in meniscus showed an organized, spatial network, in contrast to its diffuse distribution in articular cartilage. Thus, differences in the concentration, gene expression, and spatial distribution of aggrecan constitute another molecular distinction between hyaline cartilage and fibrocartilage of the knee.

Dosimetry study of [I-131] and [I-125]- meta-iodobenz guanidine in a simulating model for neuroblastoma metastasis.

Science.gov (United States)

Roa, W H; Yaremko, B; McEwan, A; Amanie, J; Yee, D; Cho, J; McQuarrie, S; Riauka, T; Sloboda, R; Wiebe, L; Loebenberg, R; Janicki, C

2013-02-01

The physical properties of I-131 may be suboptimal for the delivery of therapeutic radiation to bone marrow metastases, which are common in the natural history of neuroblastoma. In vitro and preliminary clinical studies have implied improved efficacy of I-125 relative to I-131 in certain clinical situations, although areas of uncertainty remain regarding intratumoral dosimetry. This prompted our study using human neuroblastoma multicellular spheroids as a model of metastasis. 3D dose calculations were made using voxel-based Medical Internal Radiation Dosimetry (MIRD) and dose-point-kernel (DPK) techniques. Dose distributions for I-131 and I-125 labeled mIBG were calculated for spheroids (metastases) of various sizes from 0.01 cm to 3 cm diameter, and the relative dose delivered to the tumors was compared for the same limiting dose to the bone marrow. Based on the same data, arguments were advanced based upon the principles of tumor control probability (TCP) to emphasize the potential theoretical utility of I-125 over I-131 in specific clinical situations. I-125-mIBG can deliver a higher and more uniform dose to tumors compared to I-131 mIBG without increasing the dose to the bone marrow. Depending on the tumor size and biological half-life, the relative dose to tumors of less than 1 mm diameter can increase several-fold. TCP calculations indicate that tumor control increases with increasing administered activity, and that I-125 is more effective than I-131 for tumor diameters of 0.01 cm or less. This study suggests that I-125-mIBG is dosimetrically superior to I-131-mIBG therapy for small bone marrow metastases from neuroblastoma. It is logical to consider adding I-125-mIBG to I-131-mIBG in multi-modality therapy as these two isotopes could be complementary in terms of their cumulative dosimetry.

Dynamical mechanism of charge separation by photoexcited generation of proton–electron pairs in organic molecular systems. A nonadiabatic electron wavepacket dynamics study

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Kentaro, E-mail: kyamamoto@fukui.kyoto-u.ac.jp; Takatsuka, Kazuo, E-mail: kaztak@fukui.kyoto-u.ac.jp

2016-08-22

Graphical abstract: Asymptotic biradical state produced by the excited-state coupled proton–electron transfer (CPET), resulting in charge separation (proton–electron pair creation) on a proton–electron acceptor A, in a series of photochemical systems generally denoted as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole, or ammonia clusters). - Abstract: In this perspective article, we review, along with presenting new results, a series of our theoretical analyses on the excited-state mechanism of charge separation (proton–electron pair creation) relevant to the photoinduced water-splitting reaction (2H{sub 2}O → 4H{sup +} + 4e{sup −} + O{sub 2}) in organic and biological systems, which quite often includes Mn clusters in various molecular configurations. The present mechanism is conceived to be universal in the triggering process of the photoexcited water splitting dynamics. In other words, any Mn-based catalytic charge separation is quite likely to be initiated according to this mechanism. As computationally tractable yet realistic models, we examine a series of systems generally expressed as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole or ammonia cluster) in terms of the theory of nonadiabatic electron wavepacket dynamics. We first find both an electron and a proton are simultaneously transferred to the acceptors through conical intersections upon photoexcitation. In this mechanism, the electron takes different pathways from that of the proton and reaches the densely lying Rydberg-like states of the acceptors in the end, thereby inducing charge separation. Therefore the presence of the Rydberg-like diffused unoccupied states as an electron acceptor is critical for this reaction to proceed. We also have found another crucial nonadiabatic process that deteriorates the efficiency of charge separation by rendering the created pair of proton

Theoretical study about L-arginine complexes formation with thiotriazolin

Directory of Open Access Journals (Sweden)

L. I. Kucherenko

2017-02-01

to show the possibility to form ternary complexes with low stability in infinite dilute solutions. It should be noted that two negative charges are always localized in formed complexes on the deprotonated carboxyl groups. The positive charges are located either on the guanidine moiety and the a-amino group of L-arginine, or on the guanidine moiety of L-arginine and protonated molecule of morpholine. It can be expected that the strengthening of intermolecular interactions in the real solutions may result in increased stability of the complexes.

Improving Gold Recovery from Artificial Preg-Robbing Ore by Pre-treatment using Blinding Agent and Resin-in-Leach

Directory of Open Access Journals (Sweden)

Mohammad Zaki Mubarok

2016-08-01

Full Text Available In the present paper, the effectiveness of the use of blinding agents, ionic exchanger resins and the combination of them in improving gold extraction from simulated preg-robbing ore is discussed. The blinding agents used were kerosene, diesel oil and pine oil, while the ion exchange resins used were Lewatit Monoplus MP 800, Lewatit AF 5 and guanidine. Preg-robbing conditions were simulated by blending fine activated carbon with ore sample. The investigation results show that the presence of artificial carbonaceous materials at 2% (w/w in the gold ore significantly reduces gold recovery. Pretreatment of artificial preg-robbing ore prior to cyanidation by mixing with kerosene, diesel oil and pine oil for 0.5h improved gold recovery up to 25.4%. A combination of pre-treatment using blinding agent and a resin in leach (RIL test using Lewatit MP 800 resin demonstrated a synergistic effect that improves gold recovery up to a level of 99.5%,which is significantly higher than using activated carbon and without pretreatment.

Probing the molecular forces involved in binding of selected volatile flavour compounds to salt-extracted pea proteins.

Science.gov (United States)

Wang, Kun; Arntfield, Susan D

2016-11-15

Molecular interactions between heterologous classes of flavour compounds with salt-extracted pea protein isolates (PPIs) were determined using various bond disrupting agents followed by GC/MS analysis. Flavour bound by proteins decreased in the order: dibutyl disulfide>octanal>hexyl acetate>2-octanone=benzaldehyde. Benzaldehyde, 2-octanone and hexyl acetate interacted non-covalently with PPIs, whereas octanal bound PPIs via covalent and non-covalent forces. Dibutyl disulfide reacted with PPIs covalently, as its retention was not diminished by urea and guanidine hydrochloride. Using propylene glycol, H-bonding and ionic interactions were implicated for hexyl acetate, benzaldehyde, and 2-octanone. A protein-destabilising salt (Cl3CCOONa) reduced bindings for 2-octanone, hexyl acetate, and benzaldehyde; however, retention for octanal and dibutyl disulfide increased. Conversely, a protein-stabilising salt (Na2SO4) enhanced retention for benzaldehyde, 2-octanone, hexyl acetate and octanal. Formation of a volatile flavour by-product, 1-butanethiol, from dibutyl disulfide when PPIs were treated with dithiothreitol indicated occurrence of sulfhydryl-disulfide interchange reactions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Studies on chemotherapy of parasitic helminths (VI) effects of various neuropharmacological agents on the motility of Dipylidium caninum.

Science.gov (United States)

Terada, M; Ishii, A I; Kino, H; Sano, M

1982-06-01

Effects of various neuropharmacological agents on the motility of Dipylidium caninum was studied. 5-HT stimulated the motility of D. caninum, while other drugs such as GABA, adrenaline, phenylephrine, isoproterenol, dibenamine, and propranolol showed little effect. The stimulatory action of 5-HT was antagonized by tryptophol. Stibnal caused paralysis which was blocked by the pretreatment with 5-HT. Paralytic effects were caused by eserine, dichlorovos, ACh, carbachol and DMPP, but not by pilocarpine and McN-A-343. d-Tubocurarine, hexamethonium, and atropine all showed little effect on the motility and on the paralytic action of eserine. Though guanidine showed little effect, strychnine remarkably stimulated the motility. The action of strychnine was stimulated by 5-HT but partially inhibited by tryptophol. Morphine and picrate slightly stimulated the motility, but showed little influence on the paralytic action of eserine. These two agents stimulated the paralyzed preparation by tryptophol transiently and sustainedly, respectively. These results on the cholinergic and serotonergic drugs basically showed good agreement with those reported in trematodes such as Schistosoma mansoni and Fasciola hepatica.

Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants.

Science.gov (United States)

Park, Donguk; Leem, Jonghan; Lee, Kyoungmu; Lim, Heungkyu; Choi, Yeyong; Ahn, Jong-Ju; Lim, Sinye; Park, Jeongim; Choi, Kyungho; Lee, Naroo; Jung, Hyejung; Ha, Jongsik; Paek, Domyung

2014-09-02

This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13-50 years) who used disinfectant added to humidifiers in the home. Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. Nine of the patients (three pregnant females, six preschool-age children) died soon after they first developed lung damage. Six (16%) were pregnant females and 22 (58%) were preschool-aged children younger than six years. The patients used humidifier disinfectant products containing either polyhexamethylene guanidine phosphate (PHMG, n = 36) or oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH, n = 2). Twenty-six patients (68%) used the brand "Oxy"®, which contains PHMG. Of the ten patients with fatal lung injury, nine were found to have used PHMG. Our findings suggest that the use of humidifier disinfectant products containing either PGH or PHMG can cause lung injury, especially in preschool-age children younger than six years and pregnant women.

An analysis of a humidifier disinfectant case from a toxicological perspective

Directory of Open Access Journals (Sweden)

Kwangsik Park

2016-07-01

Full Text Available An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

Preparation of novel stable antibacterial nanoparticles using hydroxyethylcellulose and application in paper.

Science.gov (United States)

Wei, Dafu; Chen, Yan; Zhang, Youwei

2016-01-20

Taking advantage of the self-assembly between the components, novel stable antibacterial nanoparticles were efficiently fabricated via a facile one-step co-polymerization of acrylic acid (AA) and N,N'-methylenebisacrylamide (MBA) on a mixed aqueous solution of poly(hexamethylene guanidine hydrochloride) (PHMG) and hydroxyethylcellulose (HEC). The z-average hydrodynamic diameters of the nanoparticles ranged from 220 nm to 450 nm. The inner layer of the nanoparticles is composed of water-insoluble interpolymer complexes of PHMG and PAA networks, while the outer layer is composed of PHMG and HEC. The nanoparticles are stabilized by electrostatic interactions, hydrogen bonding interactions, and the chemical bonds. The nanoparticle solution remained stable in a wide pH range of 2.0-12.0 and at salt concentrations below 0.25 mol/L. The nanoparticles were incorporated into handsheets using a dipping treatment. The resulted handsheets exhibited excellent antimicrobial activities even after multiple water washing treatments. The nanoparticles are promising in fabricating paper, water-based coatings and textiles with permanent antibacterial activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

An analysis of a humidifier disinfectant case from a toxicological perspective.

Science.gov (United States)

Park, Kawangsik

2016-01-01

An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG) shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

Challenges of ligand identification for the second wave of orphan riboswitch candidates.

Science.gov (United States)

Greenlee, Etienne B; Stav, Shira; Atilho, Ruben M; Brewer, Kenneth I; Harris, Kimberly A; Malkowski, Sarah N; Mirihana Arachchilage, Gayan; Perkins, Kevin R; Sherlock, Madeline E; Breaker, Ronald R

2018-03-04

Orphan riboswitch candidates are noncoding RNA motifs whose representatives are believed to function as genetic regulatory elements, but whose target ligands have yet to be identified. The study of certain orphans, particularly classes that have resisted experimental validation for many years, has led to the discovery of important biological pathways and processes once their ligands were identified. Previously, we highlighted details for four of the most common and intriguing orphan riboswitch candidates. This facilitated the validation of riboswitches for the signaling molecules c-di-AMP, ZTP, and ppGpp, the metal ion Mn 2+ , and the metabolites guanidine and PRPP. Such studies also yield useful linkages between the ligands sensed by the riboswitches and numerous biochemical pathways. In the current report, we describe the known characteristics of 30 distinct classes of orphan riboswitch candidates - some of which have remained unsolved for over a decade. We also discuss the prospects for uncovering novel biological insights via focused studies on these RNAs. Lastly, we make recommendations for experimental objectives along the path to finding ligands for these mysterious RNAs.

Slow aggregation of lysozyme in alkaline pH monitored in real time employing the fluorescence anisotropy of covalently labelled dansyl probe.

Science.gov (United States)

Homchaudhuri, Lopamudra; Kumar, Satish; Swaminathan, Rajaram

2006-04-03

The onset of hen egg white lysozyme aggregation on exposure to alkaline pH of 12.2 and subsequent slow growth of soluble lysozyme aggregates (at 298 K) was directly monitored by steady-state and time-resolved fluorescence anisotropy of covalently attached dansyl probe over a period of 24 h. The rotational correlation time accounting for tumbling of lysozyme in solution (40 microM) increased from approximately 3.6 ns (in pH 7) to approximately 40ns on exposure to pH 12.2 over a period of 6 h and remained stable thereafter. The growth of aggregates was strongly concentration dependent, irreversible after 60 min and inhibited by the presence of 0.9 M l-arginine in the medium. The day old aggregates were resistant to denaturation by 6 M guanidine.HCl. Our results reveal slow segmental motion of the dansyl probe in day old aggregates in the absence of L-arginine (0.9 M), but a much faster motion in its presence, when growth of aggregates is halted.

A new approach for the synthesis of bioactive heteroaryl thiazolidine-2,4-diones

International Nuclear Information System (INIS)

Ibrahim, Magdy Ahmed; Abdel-Hamed, Mohamed Abdel-Megid; El-Gohary, Naser Mohamed

2011-01-01

Condensation of 3-formylchromone (1) with thiazolidine-2,4-dione (2) afforded 5-[4-oxo-4Hchromen- 3-yl)methylene]-1,3-thiazolidine-2,4-dione (3). Reaction of 3 with hydrazine hydrate, phenyl hydrazine and hydroxylamine hydrochloride gave the corresponding pyrazole and isoxazole derivatives 4-7. Compound 3 was subjected to react with thiourea, guanidine and cyanoguanidine to give the corresponding pyrimidine derivatives 8-10. Pyrimido[1,2-a]pyrimidine 12, benzo[1,5] diazepine 15, pyrido[1,2-b][1,2,4]triazepine 16, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazepine 19 and 1,2,4-triazino[3,2-b][1,3,4]thiadiazepine 20 linked thiazolidine-2,4-dione were prepared from the reaction of 3 with N,N- and N,S- bifunctional nucleophiles. The chemical reactivity of 3 towards carbon nucleophiles gave new heterocyclic moieties linked thiazolidine-2,4-dione 22.25. The synthesized compounds were screened in vitro for their antimicrobial activities against Staphylococcus aureus, Proteus vulgaris and Candida albicans. (author)

Polymerase Chain Reaction (Pcr) Assay to Detect Hepatitis C Virus

International Nuclear Information System (INIS)

Lina MR; Dadang S; Budiman Bela

2004-01-01

Research on the detection of hepatitis C virus in blood serum using PCR technique has been carried out. Amount of 50 blood serum from laboratory of Indonesia Red Cross (Palang Merah Indonesia = PMI) and RSCM hospital as samples, were used in this research. Lysis of virus cell and extraction of RNA virus as a preliminary treatment of the sample, was done with BOOM method using guanidine thiocyanate and diatomaceous earth, respectively. Synthesis of cDNA from RNA as an extraction product mentioned above, was carried out by means of reverse-transcriptase and RNA-se inhibitor. Amplification of cDNA was done with nested PCR technique that was performed with two times PCR processes using two pairs of oligonucleotide primers for each process. The amplified DNA was detected by agarose gel electrophoresis and ethidium bromide staining. Subsequently, the DNA was visualized with UV transilluminator. Result shows that of 50 blood serum samples, 13 serum were positive for RNA HCV that were performed with the present of specific DNA band on agarose gel. (author)

The impact of N-glycosylation on conformation and stability of immunoglobulin Y from egg yolk.

Science.gov (United States)

Sheng, Long; He, Zhenjiao; Chen, Jiahui; Liu, Yaofa; Ma, Meihu; Cai, Zhaoxia

2017-03-01

Immunoglobulin Y (IgY) is a new therapeutic antibody, and its applications in industry are very broad. To provide insight into the effects of N-glycosylation on IgY, its conformation and stability were studied. In this research, IgY was extracted from egg yolk and then digested by peptide-N4-(N-acetyl-beta-glucosaminyl) asparagine-amidase. SDS-PAGE and infrared absorption spectrum showed that carbohydrates were distinctly reduced after enzymolysis. The circular dichroism spectrum indicated that the IgY molecule became more flexible and disordered after removal of N-glycan. The fluorescence intensity revealed that Trp residues were buried in a more hydrophobic environment after disposal of N-glycan. Storage stability decreased with the removal of oligosaccharide chains based on size-exclusion chromatography analysis. Deglycosylated IgY exhibited less resistance to guanidine hydrochloride-induced unfolding. After deglycosylation, IgY was more sensitive to pepsin. Therefore, N-glycosylation played an important role in the maintenance of the structure and stability of IgY. Copyright © 2016 Elsevier B.V. All rights reserved.

Medicinal Product Use Reglandin D-(+ - Cloprostenol, Synthetic Analogue of Prostaglandins F2α Natural Body in Fighting with Anestrus Lute (CL in Cattle

Directory of Open Access Journals (Sweden)

George Florea Tobă

2011-05-01

Full Text Available The studies made by us are based on fundamental biological role of prostaglandin modulator of hormonal actions, influxs nerve transmission and cellular ionic exchange. One of the main actions of PGF2α is luteolyse, a process that includes the secretion of progesterone and regression yellow body. PGF2α is a luteolitic for almost species: cow, buffalo, sow, mare, sheep, rabbits, guinea pigs, hamsters and rats, except primates. At present it is considered that PGF2α have their specific receptors, which are fixed and through their model would enable guanidine monophosphate or cyclic GMP's Goldberg. The effect of ocitocic luteolitic and pharmacodynamics basis of PGF2α, used in breeding biotechnologies and hormonal therapy. In medicine veterinary prostaglandines are used after 1973. Were injected with 2 ml Reglandin (150 mg D-(+ - cloprostenol 24 women diagnosed with corpus luteum anestris and 22 females (87.5% came in to oestrus at a mean of 59 hours, and after an average interval of 70 hours.şi were artificially inseminated (AI a total of 20 female (83.33%.

Pulsed Dilution Method for the Recovery of Aggregated Mouse TNF-α

Directory of Open Access Journals (Sweden)

Merat Mahmoodi

2017-05-01

Full Text Available Background: The expression of mouse tumor necrosis factor alpha (TNF-α in Escherichia coli is a favorable way to get high yield of protein; however, the formation of cytoplasmic inclusion bodies, which is the consequence of insoluble accumulated proteins, is a major obstacle in this system. To overcome this obstacle, we used a pulsed dilution method to convert the product to its native conformation. Methods: Reducing agent and guanidine hydrochloride were used to solubilize inclusion bodies formed after TNF-(α expression. Then, the refolding procedure was performed by pulsed dilution of the denatured protein into a refolding buffer. The properly-folded protein was purified by metal affinity chromatography. Results: SDS-PAGE showed a 19.9 kDa band related to the mature TNF-(α protein. The protein was recognized by anti-mouse TNF-(α on western blots. The final concentration of the purified recombinant TNF-(α was 62.5 μg/mL. Conclusions: Our study demonstrates the efficiency of this method to produce a high yield of folded mature TNF- (α.

Crystal structures of Lymnaea stagnalis AChBP in complex with neonicotinoid insecticides imidacloprid and clothianidin.

Science.gov (United States)

Ihara, Makoto; Okajima, Toshihide; Yamashita, Atsuko; Oda, Takuma; Hirata, Koichi; Nishiwaki, Hisashi; Morimoto, Takako; Akamatsu, Miki; Ashikawa, Yuji; Kuroda, Shun'ichi; Mega, Ryosuke; Kuramitsu, Seiki; Sattelle, David B; Matsuda, Kazuhiko

2008-06-01

Neonicotinoid insecticides, which act on nicotinic acetylcholine receptors (nAChRs) in a variety of ways, have extremely low mammalian toxicity, yet the molecular basis of such actions is poorly understood. To elucidate the molecular basis for nAChR-neonicotinoid interactions, a surrogate protein, acetylcholine binding protein from Lymnaea stagnalis (Ls-AChBP) was crystallized in complex with neonicotinoid insecticides imidacloprid (IMI) or clothianidin (CTD). The crystal structures suggested that the guanidine moiety of IMI and CTD stacks with Tyr185, while the nitro group of IMI but not of CTD makes a hydrogen bond with Gln55. IMI showed higher binding affinity for Ls-AChBP than that of CTD, consistent with weaker CH-pi interactions in the Ls-AChBP-CTD complex than in the Ls-AChBP-IMI complex and the lack of the nitro group-Gln55 hydrogen bond in CTD. Yet, the NH at position 1 of CTD makes a hydrogen bond with the backbone carbonyl of Trp143, offering an explanation for the diverse actions of neonicotinoids on nAChRs.

Stability of monomeric Cro variants: Isoenergetic transformation of a type I' to a type II' beta-hairpin by single amino acid replacements.

Science.gov (United States)

Mollah, A K M M; Stennis, Rhonda L; Mossing, Michael C

2003-05-01

The thermodynamic stabilities of three monomeric variants of the bacteriophage lambda Cro repressor that differ only in the sequence of two amino acids at the apex of an engineered beta-hairpin have been determined. The sequences of the turns are EVK-XX-EVK, where the two central residues are DG, GG, and GT, respectively. Standard-state unfolding free energies, determined from circular dichroism measurements as a function of urea concentration, range from 2.4 to 2.7 kcal/mole, while those determined from guanidine hydrochloride range from 2.8 to 3.3 kcal/mole for the three proteins. Thermal denaturation yields van't Hoff unfolding enthalpies of 36 to 40 kcal /mole at midpoint temperatures in the range of 53 to 58 degrees C. Extrapolation of the thermal denaturation free energies with heat capacities of 400 to 600 cal/mole deg gives good agreement with the parameters determined in denaturant titrations. As predicted from statistical surveys of amino acid replacements in beta-hairpins, energetic barriers to transformation from a type I' turn (DG) to a type II' turn (GT) can be quite small.

Recovery of copper and cyanide from waste cyanide solutions using emulsion liquid membrane with LIX 7950 as the carrier.

Science.gov (United States)

Xie, Feng; Wang, Wei

2017-08-01

The feasibility of using emulsion liquid membranes (ELMs) with the guanidine extractant LIX 7950 as the mobile carrier for detoxifying copper-containing waste cyanide solutions has been determined. Relatively stable ELMs can be maintained under suitable stirring speed during mixing ELMs and the external solution. Effective extraction of copper cyanides by ELMs only occurs at pH below 11. High copper concentration in the external phase and high volume ratio of the external phase to ELMs result in high transport rates of copper and cyanide. High molar ratio of cyanide to copper tends to suppress copper extraction. The presence of thiocyanate ion significantly depresses the transport of copper and cyanide through the membrane while the thiosulfate ion produces less impact on copper removal by ELMs. Zinc and nickel cyanides can also be effectively extracted by ELMs. More than 90% copper and cyanide can be effectively removed from alkaline cyanide solutions by ELMs under suitable experimental conditions, indicating the effectiveness of using the designed ELM for recovering copper and cyanide from waste cyanide solutions.

Biphasic insulin-releasing effect of BTS 67 582 in rats.

Science.gov (United States)

Storey, D A; Bailey, C J

1998-12-01

BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl)guanidine fumarate) is being developed as a short-acting anti-diabetic insulin secretagogue. The effect of BTS 67 582 on the phasic pattern of insulin release was assessed in anaesthetized normal rats by measuring arterial plasma insulin concentrations while arterial glucose concentrations were fixed at 6, 8.5 and 12.5 mM. Intravenous BTS 67 582 (10 mg kg(-1)) induced an immediate but transient increase in insulin concentrations which declined by 10 min (first phase). This was followed by a smaller but sustained increase in insulin concentrations (second phase). The increment from basal to peak insulin release (0-2 min) was independent of glucose, but the first phase was maintained for longer and the second phase was greater at the highest concentration of glucose (12.5 mM). BTS 67 582 also extended the first-phase insulin response to a standard intravenous glucose challenge and enhanced the rate of glucose disappearance by approximately 12%. Thus BTS 67 582 causes biphasic stimulation of insulin release and augments the insulin-releasing effect of glucose.

Induced desensitization of the insulinotropic effects of antidiabetic drugs, BTS 67 582 and tolbutamide.

Science.gov (United States)

McClenaghan, N H; Ball, A J; Flatt, P R

2000-05-01

Acute and chronic mechanisms of action of novel insulinotropic antidiabetic drug, BTS 67 582 (1, 1-dimethyl-2-(2-morpholinophenyl)guanidine fumarate), were examined in the stable cultured BRIN-BD11 cell line. BTS 67 582 (100 - 400 microM) stimulated a concentration-dependent increase (PBTS 67 582 in culture time-dependently decreased subsequent responsiveness to acute challenge with 200 microM BTS 67 582 or 200 microM tolbutamide at 12 - 18 h (PBTS 67 582 and tolbutamide. Culture with 100 microM BTS 67 582 or 100 microM tolbutamide did not affect basal insulin secretion, cellular insulin content, or cell viability and exerted no influence on the secretory responsiveness to 200 microM of the imidazoline, efaroxan. While 18 h BTS 67 582 culture did not affect the insulin-releasing actions (PBTS 67 582 shares a common signalling pathway to sulphonylurea but not imidazoline drugs. Desensitization of drug action may provide an important approach to dissect sites of action of novel and established insulinotropic antidiabetic agents.

Induction of transposon TN1 translocation under the action of different mutagens

International Nuclear Information System (INIS)

Kubanejshvili, M.G.; Smirnov, S.P.; Tarasov, V.A.

1983-01-01

Migration of ampicillin transposon Tn1 under normal conditions in Escherichia coli cells proceeds with low frequency (10 -4 transpositions for cell). The low transposition frequency is conditioned by the transposition repression, realized by the gene-repressor in transposon structure and, probably, by other regulating genes of the bacterium-host. E. coli cell treatment by physical and chemical mutagens resulted in induction of translocation of ampicillin transposon Tn1 from plasmid RP4 into other replicons. Mitomycin C and ultraviolet radiation produced stronger inducing effect as compared to nitroso-guanidine (NG). The effect of the given mutagens on transposition Tn1 correlated with their activating capacity with respect to inducible SOS-functions of E coli. The mutation of rec A didn't influence on spontaneous Tn1 transposition, but blocked completely the induction of transposition process under mutagen effect. The relationship of inducible transposition with SOS-functions in E. coli cells, controlled by recA and lexA genes, as well as the possible role of the process in genetic microorganism variability are discussed in the paper

A waterproofing agent

Energy Technology Data Exchange (ETDEWEB)

Shchipanov, A.I.; Bass, U.M.; Belousov, E.D.; Chernova, S.P.; Gioev, K.A.; Perlin, L.M.; Shapiro, B.O.; Silantev, U.R.

1979-12-25

A waterproofing agent is proposed with improved physiomechanical properties. The agent contains (by parts): bitumens: 100; emulsifier: .6-5; polyvinylpyrrolidone: .4-8; synthetic latex: 5.24; a corrosion inhibitor: .2-10; SPL methyl methacrylate with chloroprene: 2.24; hydrochlorinated amine of adduct diethylene triamine with diglycidyl diamine: 2-10, water: 118-220. The agent is prepared using either periodic or continuous action in emulsifying dispersion machines. The bitumen is dispersed in the machine in an aqueous emulsifying solution in which polyvinylpyrrolidone and the corrosion inihibitor are first introduced. Then a synthetic latex solution is introduced into the bitumen emulsion while being mixed in rotor-type turbulent mixers; a solution and a hydrochlorinated amine of adduct diethylene triamine with diglycidyl diamine solution until a homogeneous mixture is obtained. Example: a waterproofing agent is obtained in parts: bitumen 100, emulsifyer (oxidized petrolatum): .6; polyvinylpyrrolidone: .4; synthetic latex (nitrile): 5; corrosion inhibitor (guanidine chromate): .2, SPL:2; and water 118. The properties of the proposed composition are better than the properties of the composition currently used.

A new approach for the synthesis of bioactive heteroaryl thiazolidine-2,4-diones

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Magdy Ahmed; Abdel-Hamed, Mohamed Abdel-Megid; El-Gohary, Naser Mohamed, E-mail: magdy_ahmed1977@yahoo.co [Ain Shams University, Roxy, Cairo (Egypt). Faculty of Education. Dept. of Chemistry

2011-07-01

Condensation of 3-formylchromone (1) with thiazolidine-2,4-dione (2) afforded 5-[4-oxo-4Hchromen- 3-yl)methylene]-1,3-thiazolidine-2,4-dione (3). Reaction of 3 with hydrazine hydrate, phenyl hydrazine and hydroxylamine hydrochloride gave the corresponding pyrazole and isoxazole derivatives 4-7. Compound 3 was subjected to react with thiourea, guanidine and cyanoguanidine to give the corresponding pyrimidine derivatives 8-10. Pyrimido[1,2-a]pyrimidine 12, benzo[1,5] diazepine 15, pyrido[1,2-b][1,2,4]triazepine 16, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazepine 19 and 1,2,4-triazino[3,2-b][1,3,4]thiadiazepine 20 linked thiazolidine-2,4-dione were prepared from the reaction of 3 with N,N- and N,S- bifunctional nucleophiles. The chemical reactivity of 3 towards carbon nucleophiles gave new heterocyclic moieties linked thiazolidine-2,4-dione 22.25. The synthesized compounds were screened in vitro for their antimicrobial activities against Staphylococcus aureus, Proteus vulgaris and Candida albicans. (author)

Hamster female protein, a pentameric oligomer capable of reassociation and hybrid formation

International Nuclear Information System (INIS)

Coe, J.E.; Ross, M.J.

1987-01-01

Syrian hamster female protein (SFP), a serum oligomer composed of five identical subunits, was reassociated in vitro monomer subunits. The reconstituted pentamer was genuine by morphologic, antigenic, and structural criteria. Another female protein (FP), a homologue from Armenian hamsters (AFP), also reassociated into a pentamer after dissociation with 5 M guanidine hydrochloride. These two FP's hybridized when a mixture of them was dissociated and then reassociated. Differences between the parent FP's were used to show that the recombinant pentamer contained monomer subunits from both SFP and AFP. Reassociation of both FP's was enhanced by increasing FP concentration and also by adding Ca 2+ during reassembly. The two FP's differed in their reassociation profile in that SFP was especially efficient in reassembly, whereas AFP was more dependent upon Ca 2+ . Female protein is a homologue of C-reactive protein and amyloid P component, and all of these proteins (pentraxins) share a similar structure. The in vitro dissociation-reassociation of female protein described herein may reflect an in vivo dissociation-reassociation which is functionally important and a common metabolic feature within this family of proteins

Red blood cells in cerebrospinal fluid as possible inhibitory factor for enterovirus RT-PCR

Directory of Open Access Journals (Sweden)

Sérgio Monteiro de Almeida

Full Text Available ABSTRACT The presence of hemoglobin in samples are considered an important inhibitory factor for polymerase chain reaction (PCR. The aim of this study was to examine the influence of red blood cells (RBCs in cerebrospinal fluid (CSF as an inhibitory factor to reverse transcription polymerase chain reaction (RT-PCR for enteroviruses (EV. Forty-four CSF samples from patients showing characteristics of viral meningitis were assessed for EV by RT-PCR. Viral RNA extracted with guanidine isothyocianate buffer and virus detection was performed by in-house nested PCR. Positivity for EV RT-PCR was higher in CSF samples without RBCs than in samples with RBCs: 13(26% and 36(9.2%, p = 0.001. In the group with positive EV RT-PCR, the mean + SD CSF RBC was 37 ± 183 cell/mm3; the group with negative results had 580 + 2,890 cell/mm3 (p = 0.007. The acceptable upper limit for CSF RBCs that could not influence RT-PCR was 108 cells/mm3. CSF samples with negative results for EV RT-PCR have more erythrocytes.

Validation data supporting the characterization of novel copper complexes as anticancer agents

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Ceyda Acilan

2016-12-01

Full Text Available Three copper(II complexes, Cu(Sal-Gly(phen, Cu(Sal-Glypheamine, Cu(Sal-Glyphepoxy were synthesized and characterized for their anticancer properties and mechanism of action (Acilan et al., in press [1]. Here, we provide supporting data on colon cancer cell lines complementing our previous findings in cervix cells. This paper also contains a data table for the fold changes and p-values of all genes analyzed in this study via a custom RT-qPCR array. All compounds induced DNA damage (based on 8-oxo-guanidine, ɣH2AX staining in cells and apoptosis (based on elevated DNA condensation/fragmentation, Annexin V staining, caspase 3/7 activity and mitochondrial membrane depolarization in HCT-116 colon cancer cells. The increase in oxidative stress was also further confirmed in these cells. Further interpretation of the data presented here can be found in the article entitled “Synthesis, biological characterization and evaluation of molecular mechanisms of novel copper complexes as anticancer agents” (Acilan et al., in press [1].

Combined experimental and numerical kinetic characterization of NR vulcanized with sulphur, N terbutyl, 2 benzothiazylsulphenamide and N,N diphenyl guanidine

Energy Technology Data Exchange (ETDEWEB)

Milani, G., E-mail: gabriele.milani@polimi.it [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Hanel, T.; Donetti, R. [Pirelli Tyre, Via Alberto e Piero Pirelli 25, 20126 Milan (Italy); Milani, F. [Chem. Co, Via J.F.Kennedy 2, 45030 Occhiobello (Italy)

2016-06-08

The paper presents the final results of a comprehensive experimental and numerical analysis aimed at deeply investigating the behavior of Natural Rubber (NR) vulcanized with sulphur in presence of different accelerators during standard rheometer tests. NR in presence of sulphur and two different accelerators (DPG and TBBS) in various concentrations is investigated, changing the curing temperature in the range 150-180°C and obtaining rheometer curves with a step of 10°C. Sulphur-TBBS concentrations considered are 1-1, 1-3, 3-3 and 3-1, with DPG at 1-4 phr respectively. A total of 48 experimental rheometer curves is so obtained. To fit experimental data, the general reaction scheme proposed by Han and co-workers for vulcanized sulphur NR is re-adapted and suitably modified taking into account the single contributions of the different accelerators. Chain reactions initiated by the formation of macro-compounds responsible for the formation of the unmatured crosslinked polymer are accounted for. In presence of two accelerators, reactions are assumed to proceed in parallel, making the practically effective hypothesis that there is no interaction between the two accelerators. From the simplified kinetic scheme adopted, a closed form solution is found for the crosslink density, with the only limitation that the induction period is excluded from computations. For each experimented case on the same blend, reaction kinetic constants provided by the model are utilized to deduce their trend in the Arrhenius space, also outside the temperature range inspected. Rather close linearity is found in the majority of the cases. A comparative analysis is carefully conducted among the constants at the different concentrations of S, TBBS and DPG investigated, allowing a prediction of curing behavior at any vulcanization temperature and with concentrations not experimentally tested, without the need of addition costly experimentation.

MOCVD of zirconium oxide from the zirconium guanidinate complex |ZrCp′{2-(iPrN)2CNMe2}2Cl

NARCIS (Netherlands)

Blackman, C.S.; Carmalt, C.J.; Moniz, S.J.A.; Potts, S.E.; Davies, H.O.; Pugh, D.C.

2009-01-01

Parallel to successful studies into use of [ZrCp'{¿ 2-(iPrN)2CNMe2} 2Cl] as a precursor to the deposition of zirconium carbonitride via CVD the same precursor was utilised for the MOCVD of thin films of ZrO 2 using borosilicate glass substrates. The deposited films were of mixed phase; films

Combined experimental and numerical kinetic characterization of NR vulcanized with sulphur, N terbutyl, 2 benzothiazylsulphenamide and N,N diphenyl guanidine

International Nuclear Information System (INIS)

Milani, G.; Hanel, T.; Donetti, R.; Milani, F.

2016-01-01

The paper presents the final results of a comprehensive experimental and numerical analysis aimed at deeply investigating the behavior of Natural Rubber (NR) vulcanized with sulphur in presence of different accelerators during standard rheometer tests. NR in presence of sulphur and two different accelerators (DPG and TBBS) in various concentrations is investigated, changing the curing temperature in the range 150-180°C and obtaining rheometer curves with a step of 10°C. Sulphur-TBBS concentrations considered are 1-1, 1-3, 3-3 and 3-1, with DPG at 1-4 phr respectively. A total of 48 experimental rheometer curves is so obtained. To fit experimental data, the general reaction scheme proposed by Han and co-workers for vulcanized sulphur NR is re-adapted and suitably modified taking into account the single contributions of the different accelerators. Chain reactions initiated by the formation of macro-compounds responsible for the formation of the unmatured crosslinked polymer are accounted for. In presence of two accelerators, reactions are assumed to proceed in parallel, making the practically effective hypothesis that there is no interaction between the two accelerators. From the simplified kinetic scheme adopted, a closed form solution is found for the crosslink density, with the only limitation that the induction period is excluded from computations. For each experimented case on the same blend, reaction kinetic constants provided by the model are utilized to deduce their trend in the Arrhenius space, also outside the temperature range inspected. Rather close linearity is found in the majority of the cases. A comparative analysis is carefully conducted among the constants at the different concentrations of S, TBBS and DPG investigated, allowing a prediction of curing behavior at any vulcanization temperature and with concentrations not experimentally tested, without the need of addition costly experimentation.

Determination of disulfide bridges of two spider toxins: hainantoxin-III and hainantoxin-IV

Directory of Open Access Journals (Sweden)

W Wang

2009-01-01

Full Text Available Peptide toxins are usually highly bridged proteins with multipairs of intrachain disulfide bonds. Analysis of disulfide connectivity is an important facet of protein structure determination. In this paper, we successfully assigned the disulfide linkage of two novel peptide toxins, called HNTX-III and HNTX-IV, isolated from the venom of Ornithoctonus hainana spider. Both peptides are useful inhibitors of TTX-sensitive voltage-gated sodium channels and are composed of six cysteine residues that form three disulfide bonds, respectively. Firstly, the peptides were partially reduced by tris(2-carboxyethyl-phosphine (TCEP in 0.1 M citrate buffer containing 6 M guanidine-HCl at 40° C for ten minutes. Subsequently, the partially reduced intermediates containing free thiols were separated by reversed-phase high-performance liquid chromatography (RP-HPLC and alkylated by rapid carboxamidomethylation. Then, the disulfide bonds of the intermediates were analyzed by Edman degradation. By using the strategy above, disulfide linkages of HNTX-III and HNTX-IV were determined as I-IV, II-V and III-VI pattern. In addition, this study also showed that this method may have a great potential for determining the disulfide bonds of spider peptide toxins.

Radiopharmaceuticals for diagnosis and treatment: Progress report for the period November 1, 1968 through July 1, 1987

International Nuclear Information System (INIS)

Kuhl, D.E.

1987-07-01

This project has been directed to the evolution of labeled chemicals useful for nuclear medical imaging to trace adrenal functions and localizing tumors in the neuroendocrine system. A major success was the introduction of 131 I-metaiodobenzylguanidine (MIBG). The uptake of radiolabeled precursors of epinephrine was explored. The uptake and excretion of five C-14 labeled precursors of epinephrine was studied in dogs. The adrenal medulla uptake of C-14 dopamine exceeded that of all other precursors. During the initial attempts to synthesize a successful adrenal medulla imaging agent, the concentration of C-14 dopamine in the human neuroblastoma was found to be considerably greater than in the normal human adrenal medulla. Radioiodinated bretylium analog was prepared that images the dog adrenal medulla. This effort was rapidly followed by the synthesis of original compounds with structural similarities to both norepinephrine and the adrenergic neuronal blocking agent, guanethidine; these latter agents demonstrating greater adrenal medulla specificity than the bretylium analogs. One of these guanidine derivatives, 131 I-metaiodobenzylguanidine (MIBG) has permitted the first successful diagnostic imaging of human adrenal medullary hyperplasia and of pheochromocytomas (including metastasized carcinoma) which could not be localized by any existing methodologies

Application of Tryptophan Fluorescence Bandwidth-Maximum Plot in Analysis of Monoclonal Antibody Structure.

Science.gov (United States)

Huang, Cheng-Yen; Hsieh, Ming-Ching; Zhou, Qinwei

2017-04-01

Monoclonal antibodies have become the fastest growing protein therapeutics in recent years. The stability and heterogeneity pertaining to its physical and chemical structures remain a big challenge. Tryptophan fluorescence has been proven to be a versatile tool to monitor protein tertiary structure. By modeling the tryptophan fluorescence emission envelope with log-normal distribution curves, the quantitative measure can be exercised for the routine characterization of monoclonal antibody overall tertiary structure. Furthermore, the log-normal deconvolution results can be presented as a two-dimensional plot with tryptophan emission bandwidth vs. emission maximum to enhance the resolution when comparing samples or as a function of applied perturbations. We demonstrate this by studying four different monoclonal antibodies, which show the distinction on emission bandwidth-maximum plot despite their similarity in overall amino acid sequences and tertiary structures. This strategy is also used to demonstrate the tertiary structure comparability between different lots manufactured for one of the monoclonal antibodies (mAb2). In addition, in the unfolding transition studies of mAb2 as a function of guanidine hydrochloride concentration, the evolution of the tertiary structure can be clearly traced in the emission bandwidth-maximum plot.

Elastin binds to a multifunctional 67-kilodalton peripheral membrane protein

International Nuclear Information System (INIS)

Mecham, R.P.; Hinek, A.; Entwistle, R.; Wrenn, D.S.; Griffin, G.L.; Senior, R.M.

1989-01-01

Elastin binding proteins from plasma membranes of elastin-producing cells were isolated by affinity chromatography on immobilized elastin peptides. Three proteins of 67, 61, and 55 kDa were released from the elastin resin by guanidine/detergent, soluble elastin peptides, synthetic peptide VGVAPG, or galactoside sugars, but not by synthetic RGD-containing peptide or sugars not related to galactose. All three proteins incorporated radiolabel upon extracellular iodination and contained [ 3 H]leucine following metabolic labeling, confirming that each is a synthetic product of the cell. The 67-kDa protein could be released from the cell surface with lactose-containing buffers, whereas solubilization of the 61- and 55-kDa components required the presence of detergent. Although all three proteins were retained on elastin affinity columns, the 61- and 55-kDa components were retained only in the presence of 67-kDa protein, suggesting that the 67-kDa protein binds elastin and the 61- and 55-kDa proteins bind to the 67-kDa protein. The authors propose that the 67-, 61-, and 55-kDa proteins constitute an elastin-receptor complex that forms a transmembrane link between the extracellular matrix and the intracellular compartment

Antibacterial performance of polypropylene nonwoven fabric wound dressing surfaces containing passive and active components

Energy Technology Data Exchange (ETDEWEB)

Xin, Zhirong, E-mail: xinzhirong2012@126.com [School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005 (China); Du, Shanshan; Zhao, Chunyu; Chen, Hao; Sun, Miao [School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005 (China); Yan, Shunjie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Luan, Shifang, E-mail: sfluan@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin, Jinghua [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2016-03-01

Graphical abstract: - Highlights: • PNVP and PHMG components were covalently immobilized on PP{sub NWF} surface. • PP{sub NWF}-g-PNVP-PHMG possessed bacterial adhesion-resistant and bactericidal capabilities. • PP{sub NWF}-g-PNVP-PHMG obviously suppressed platelet and red blood cell adhesion. - Abstract: A growing number of wound dressing-related nosocomial infections necessitate the development of novel antibacterial strategies. Herein, polypropylene non-woven fabric (PP{sub NWF}) was facilely modified with passive and active antibacterial components, namely photografting polymerization both N-Vinyl-2-pyrrolidone (NVP) and glycidyl methacrylate (GMA) monomers, and the introduction of guanidine polymer through the reaction between active amino groups and epoxy groups. The modified samples were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), respectively. Water contact angle measurement, antibacterial test, platelet and red blood cell adhesion were used to evaluate the hydrophilicity, antibacterial properties and hemocompatibility of the samples. It was found that the antibacterial properties were obviously enhanced, meanwhile significantly suppressing platelet and red blood cell adhesion after the above modification. This PP{sub NWF} samples that possess antifouling and antimicrobial properties, have great potential in wound dressing applications.

An analytical method for estimating the 14N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

International Nuclear Information System (INIS)

Iselin, L.H.

1992-01-01

The use of 14 N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing 14 N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The 14 N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation

Novel insight into antimicrobial resistance and sensitivity phenotypes associated to qac and norA genotypes in Staphylococcus aureus.

Science.gov (United States)

Marchi, Emmanuela; Furi, Leonardo; Arioli, Stefania; Morrissey, Ian; Di Lorenzo, Valeria; Mora, Diego; Giovannetti, Luciana; Oggioni, Marco Rinaldo; Viti, Carlo

2015-01-01

Staphylococcus aureus strains harboring QacA, QacB, QacC, QacG transporters and norA promoter up-regulating mutations were characterized by phenotype microarray (PM), standard methods for susceptibility testing, and ethidium bromide efflux assays, in order to increase knowledge on phenotypes associated to efflux pumps and their substrates. PM data and standard susceptibility testing lead to the identification of new potential efflux targets, such as guanidine hydrochloride or 8-hydroxyquinoline for QacA and QacC pumps, respectively. The identification of compounds to which the presence of efflux pumps induced increased susceptibility opens new perspectives for potential adjunct anti-resistance treatment (i.e. strains bearing QacB transporters showed increased susceptibility to thioridazine, amitriptyline and orphenadrine). Although the tested isolates were characterized by high degree of heterogeneity, a hallmark of clinical isolates, direct ethidium bromide efflux assays were effective in highlighting differences in efflux efficiency among strains. These data add to characterization of substrate specificity in the different classes of staphylococcal multidrug efflux systems conferring specific substrate profiles and efflux features to each of them. Copyright © 2014 Elsevier GmbH. All rights reserved.

Class I ADP-ribosylation factors are involved in enterovirus 71 replication.

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Jianmin Wang

Full Text Available Enterovirus 71 is one of the major causative agents of hand, foot, and mouth disease in infants and children. Replication of enterovirus 71 depends on host cellular factors. The viral replication complex is formed in novel, cytoplasmic, vesicular compartments. It has not been elucidated which cellular pathways are hijacked by the virus to create these vesicles. Here, we investigated whether proteins associated with the cellular secretory pathway were involved in enterovirus 71 replication. We used a loss-of-function assay, based on small interfering RNA. We showed that enterovirus 71 RNA replication was dependent on the activity of Class I ADP-ribosylation factors. Simultaneous depletion of ADP-ribosylation factors 1 and 3, but not three others, inhibited viral replication in cells. We also demonstrated with various techniques that the brefeldin-A-sensitive guanidine nucleotide exchange factor, GBF1, was critically important for enterovirus 71 replication. Our results suggested that enterovirus 71 replication depended on GBF1-mediated activation of Class I ADP-ribosylation factors. These results revealed a connection between enterovirus 71 replication and the cellular secretory pathway; this pathway may represent a novel target for antiviral therapies.

The use of radiolabelled milk proteins to study thermally-induced interactions in milk systems

International Nuclear Information System (INIS)

Noh, B.

1988-01-01

Heat induced complexes between milk proteins are of considerable importance in determining the heat stability and rennin clottability of milk products. Thiol-disulfide interchange reactions have been suggested as the principal reaction mechanism for complex formation. Studies to data have not adequately established the mechanism and stoichiometry of complex formation in situ in total milk system. Tracer amounts of 14 C-β-lactoglobulin and α-lactalbumin were heated under various conditions. After clotting with rennet, radioactivity retained in the curd was counted to estimate extent of interaction of β-lactoglobulin with casein. 14 C- and 3 H-Methyl labelled proteins were used for the preparation of radiolabelled artificial casein micelles. These micelles with radiolabelled whey proteins were heated and heat-induced complexes were separated on Sephacryl S-300 eluting with 6 M guanidine hydrochloride to break all non-covalent bonds. Further separation of the protein complexes was obtained using CPG-10 or Sephacryl S-1000. The ratios of 3 H to 14 C labelled proteins in the protein complexes suggested that the stoichiometries of k-, α s2 -casein, β-lactoglobulin and α-lactalbumin in the heat-induced complexes varied as a function of the heat treatment

Structural organization of poliovirus RNA replication is mediated by viral proteins of the P2 genomic region

International Nuclear Information System (INIS)

Bienz, K.; Egger, D.; Troxler, M.; Pasamontes, L.

1990-01-01

Transcriptionally active replication complexes bound to smooth membrane vesicles were isolated from poliovirus-infected cells. In electron microscopic, negatively stained preparations, the replication complex appeared as an irregularly shaped, oblong structure attached to several virus-induced vesicles of a rosettelike arrangement. Electron microscopic immunocytochemistry of such preparations demonstrated that the poliovirus replication complex contains the proteins coded by the P2 genomic region (P2 proteins) in a membrane-associated form. In addition, the P2 proteins are also associated with viral RNA, and they can be cross-linked to viral RNA by UV irradiation. Guanidine hydrochloride prevented the P2 proteins from becoming membrane bound but did not change their association with viral RNA. The findings allow the conclusion that the protein 2C or 2C-containing precursor(s) is responsible for the attachment of the viral RNA to the vesicular membrane and for the spatial organization of the replication complex necessary for its proper functioning in viral transcription. A model for the structure of the viral replication complex and for the function of the 2C-containing P2 protein(s) and the vesicular membranes is proposed

Employment of the technique of radiotracers for analysis of industrial filters

International Nuclear Information System (INIS)

Ramos, Vitor Santos; Crispim, Verginia Reis

2007-01-01

The main aim of this work is to develop a methodology to evaluate the characteristics of porous media in filter using the radio-tracing technique. To do this, an experimental prototype filter made up of an acrylic cylinder, vertically mounted and supported on the lower side by a controlled leaking valve was developed. Two filters (spheres of acrylic and silica crystals) were used to check the movement of the water through the porous media using 123 I in its MIBG (iodine-123-meta-iodo benzyl-guanidine) form. Further up the filter an instantaneous injection of the substance makes it possible to see the passage of radioactive clouds through the two scintillatory detectors NaI (2x2) ' ' positioned before and immediately after the cylinder with the filtering element (porous media). The are caused by the detectors on the passage of the radioactive cloud are analyzed through statistical functions using the weighted moment method which makes it possible to calculate the Residence-Time (the amount of time the tracer takes to thoroughly pass through the filter) per the equation of dispersion in tubular flow and the one-directional flow of the radiotracer in the porous media. (author)

Regulation of spermidine/spermine N1-acetyltransferase in L6 cells by polyamines and related compounds.

Science.gov (United States)

Erwin, B G; Pegg, A E

1986-01-01

Exposure of rat L6 cells in culture to exogenous polyamines led to a very large increase in the activity of spermidine/spermine N1-acetyltransferase. Spermine was more potent than spermidine in bringing about this increase, but in both cases the elevated acetyltransferase activity increased the cellular conversion of spermidine into putrescine. The N1-acetyltransferase turned over very rapidly in the L6 cells, with a half-life of 9 min after spermidine and 18 min after spermine. A wide variety of synthetic polyamine analogues also brought about a substantial induction of spermidine/spermine N1-acetyltransferase activity. These included sym-norspermidine, sym-norspermine, sym-homospermidine, N4-substituted spermidine derivatives, 1,3,6-triaminohexane, 1,4,7-triaminoheptane and deoxyspergualin, which were comparable with spermidine in their potency, and N1N8-bis(ethyl)spermidine, N1N9-bis(ethyl)homospermidine, methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone) and 1,1'-[(methylethanediylidene)dinitrilo]bis(3-amino-guanidine ), which were even more active than spermidine. It is suggested that these polyamine analogues may bring about a decrease in cellular polyamines not only by inhibiting biosynthesis but by stimulating the degradation of spermidine into putrescine. PMID:3800951

Comparison of Different Sample Preparation Protocols Reveals Lysis Buffer-Specific Extraction Biases in Gram-Negative Bacteria and Human Cells.

Science.gov (United States)

Glatter, Timo; Ahrné, Erik; Schmidt, Alexander

2015-11-06

We evaluated different in-solution and FASP-based sample preparation strategies for absolute protein quantification. Label-free quantification (LFQ) was employed to compare different sample preparation strategies in the bacterium Pseudomonas aeruginosa and human embryonic kidney cells (HEK), and organismal-specific differences in general performance and enrichment of specific protein classes were noted. The original FASP protocol globally enriched for most proteins in the bacterial sample, whereas the sodium deoxycholate in-solution strategy was more efficient with HEK cells. Although detergents were found to be highly suited for global proteome analysis, higher intensities were obtained for high-abundant nucleic acid-associated protein complexes, like the ribosome and histone proteins, using guanidine hydrochloride. Importantly, we show for the first time that the observable total proteome mass of a sample strongly depends on the sample preparation protocol, with some protocols resulting in a significant underestimation of protein mass due to incomplete protein extraction of biased protein groups. Furthermore, we demonstrate that some of the observed abundance biases can be overcome by incorporating a nuclease treatment step or, alternatively, a correction factor for complementary sample preparation approaches.

Effect of Hofmeister series salts on Absorptivity of aqueous solutions on Sodium polyacrylate

Science.gov (United States)

Korrapati, Swathi; Pullela, Phani Kumar; Vijayalakshmi, U.

2017-11-01

Sodium polyacrylate (SPA) is a popular super absorbent commonly used in children diapers, sanitary pads, adult diapers etc. The use of SPA is in force from past 30 years and the newer applications like as food preservant are evolving. SPA is recently discovered by our group for improvement of sensitivity of colorimetric agents. Though the discovery of improvement in sensitivity is phenomenal, the mechanism still remains a puzzle. A typical assay reagent contains colorimetric/fluorescent reagents, buffers, salts, stabilizers etc. These chemicals are known to influence the water absorptivity of SPA. If we were to perform chemical/biochemical assays on SPA absorbed reagents effect of salts and other excipients on colorimetric/fluorescence compounds absorbed on SPA is very important. The hofmeister series are standard for studying effect of salts on permeability, stability, aggregation, fluorescence quenching etc. We recently studied affect of urea, sodium chloride, ammonium sulfate, guanidine thiocayanate on fluorescence characteristics of fluorescence compounds and noted that except urea all other reagents have resulted in fluorescence quenching and urea had an opposite effect and increased the fluorescence intensity. This result was attributed to the different water structure around fluorescent in urea solution versus other chaotropic agents.

Biodistribution of 99m technetium labeled creatinine in healthy rats

International Nuclear Information System (INIS)

Yilmaz, O.; Soylu, A.; Kavukcu, S.; Lambrecht, F. Yurt; Durkan, K.

2007-01-01

The distribution of creatinine, one of the toxic guanidine compounds, in various tissues has not been studied in detail by using radiolabeled creatinine. Our objective was to investigate the biodistribution of creatinine labeled with 99m technetium ( 99m Tc) by the stannous (II) chloride method in healthy male Wistar rats. Quality controls were carried out by radio thin layer chromatography, high-performance liquid chromatography, and paper electrophoresis. The labeling yield was 85 ± 2% under optimum conditions (pH 7 and 100 μg stannous chloride). Rats (N 12) were injected intravenously with 99m Tc creatinine and their blood and visceral organs were evaluated for 99m Tc-creatinine uptake as percent of the injected dose per gram wet weight of each tissue (%ID/g). The lowest amount of uptake was detected in the brain and testis. When the rate of uptake was evaluated, only the kidney showed increasing rates of uptake of 99m Tc-creatinine throughout the study. Kidneys showed the highest amount of uptake throughout the study (P < 0.001 compared to all other organs), followed by liver, spleen and lung tissue. (author)

Biodistribution of {sup 99m} technetium labeled creatinine in healthy rats

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, O. [Dokuz Eylul University, Narlidere, Izmir (Turkey). Medical Faculty. Dept. of Animal Research Center; Soylu, A.; Kavukcu, S. [Dokuz Eylul University, Narlidere, Izmir (Turkey). Medical Faculty. Dept. of Pediatrics; Lambrecht, F. Yurt; Durkan, K. [Ege University, Bornova, Izmir (Turkey). Institute of Nuclear Sciences. Dept. of Nuclear Applications]. E-mail: s.kavukcu@deu.edu.tr

2007-06-15

The distribution of creatinine, one of the toxic guanidine compounds, in various tissues has not been studied in detail by using radiolabeled creatinine. Our objective was to investigate the biodistribution of creatinine labeled with {sup 99m}technetium ({sup 99m} Tc) by the stannous (II) chloride method in healthy male Wistar rats. Quality controls were carried out by radio thin layer chromatography, high-performance liquid chromatography, and paper electrophoresis. The labeling yield was 85 {+-} 2% under optimum conditions (pH 7 and 100 {mu}g stannous chloride). Rats (N 12) were injected intravenously with {sup 99m} Tc creatinine and their blood and visceral organs were evaluated for {sup 99m} Tc-creatinine uptake as percent of the injected dose per gram wet weight of each tissue (%ID/g). The lowest amount of uptake was detected in the brain and testis. When the rate of uptake was evaluated, only the kidney showed increasing rates of uptake of {sup 99m} Tc-creatinine throughout the study. Kidneys showed the highest amount of uptake throughout the study (P < 0.001 compared to all other organs), followed by liver, spleen and lung tissue. (author)

123I-MIBG myocardial imaging in hypertensive patients. Abnormality progresses with left ventricular hypertrophy

International Nuclear Information System (INIS)

Mitani, Isao; Sumita, Shinichi; Takahashi, Nobukazu; Ochiai, Hisao; Ishii, Masao

1996-01-01

Twenty-seven patients with essential hypertension were prospectively studied with 123 I-labeled metaiodobenzyl-guanidine ( 123 I-MIBG) to assess the presence and location of impaired sympathetic innervation in hypertrophied myocardium. Thirteen patients had left ventricular hypertrophy on echocardiography, and 14 had normal echocardiograms. The wash-out ratio of 123 I-MIBG in these two groups did not differ significantly (35.3±6.1 and 35.4±5.1) but was higher than in control subjects (29.4±6.7). The delayed heart-to-mediastinum count ratio was lower in the patients with hypertrophy than in the patients without hypertrophy (1.93±0.28 and 2.22±0.21; p<0.05) and the control subjects (1.93±0.28 and 2.33±0.25; p<0.05). On SPECT imaging, abnormalities in segmental uptake were frequent at the posterior and postero-lateral wall in both groups, although the hypertrophic group had more significant impairment. Our results lead to the hypothesis that hypertension in more advanced stages may be associated not only with hypertrophic changes but also with more advanced regional impairment of cardiac sympathetic innervation. (author)

Characteristics of recombinantly expressed rat and human histamine H3 receptors.

Science.gov (United States)

Wulff, Birgitte S; Hastrup, Sven; Rimvall, Karin

2002-10-18

Human and rat histamine H(3) receptors were recombinantly expressed and characterized using receptor binding and a functional cAMP assay. Seven of nine agonists had similar affinities and potencies at the rat and human histamine H(3) receptor. S-alpha-methylhistamine had a significantly higher affinity and potency at the human than rat receptor, and for 4-[(1R*,2R*)-2-(5,5-dimethyl-1-hexynyl)cyclopropyl]-1H-imidazole (Perceptin) the preference was the reverse. Only two of six antagonists had similar affinities and potencies at the human and the rat histamine H(3) receptor. Ciproxifan, thioperamide and (1R*,2R*)-trans-2-imidazol-4 ylcyclopropyl) (cyclohexylmethoxy) carboxamide (GT2394) had significantly higher affinities and potencies at the rat than at the human histamine H(3) receptor, while for N-(4-chlorobenzyl)-N-(7-pyrrolodin-1-ylheptyl)guanidine (JB98064) the preference was the reverse. All antagonists also showed potent inverse agonism properties. Iodoproxyfan, Perceptin, proxyfan and GR175737, compounds previously described as histamine H(3) receptor antagonists, acted as full or partial agonists at both the rat and the human histamine H(3) receptor. Copyright 2002 Elsevier Science B.V.

Induced desensitization of the insulinotropic effects of antidiabetic drugs, BTS 67 582 and tolbutamide

Science.gov (United States)

McClenaghan, Neville H; Ball, Andrew J; Flatt, Peter R

2000-01-01

Acute and chronic mechanisms of action of novel insulinotropic antidiabetic drug, BTS 67 582 (1,1-dimethyl-2-(2-morpholinophenyl)guanidine fumarate), were examined in the stable cultured BRIN-BD11 cell line. BTS 67 582 (100–400 μM) stimulated a concentration-dependent increase (PBTS 67 582 in culture time-dependently decreased subsequent responsiveness to acute challenge with 200 μM BTS 67 582 or 200 μM tolbutamide at 12–18 h (PBTS 67 582 and tolbutamide. Culture with 100 μM BTS 67 582 or 100 μM tolbutamide did not affect basal insulin secretion, cellular insulin content, or cell viability and exerted no influence on the secretory responsiveness to 200 μM of the imidazoline, efaroxan. While 18 h BTS 67 582 culture did not affect the insulin-releasing actions (PBTS 67 582 shares a common signalling pathway to sulphonylurea but not imidazoline drugs. Desensitization of drug action may provide an important approach to dissect sites of action of novel and established insulinotropic antidiabetic agents. PMID:10807689

Effect of quencher, denaturants, temperature and pH on the fluorescent properties of BSA protected gold nanoclusters

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Chib, Rahul, E-mail: Rahul.chib@live.unthsc.edu [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Butler, Susan [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Raut, Sangram [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Shah, Sunil; Borejdo, Julian [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Gryczynski, Zygmunt [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Gryczynski, Ignacy, E-mail: ignacy.gryczynski@unthsc.edu [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

2015-12-15

In this paper, we have synthesized BSA protected gold nanoclusters (BSA Au nanocluster) and studied the effect of quencher, protein denaturant, pH and temperature on the fluorescence properties of the tryptophan molecule of the BSA Au nanocluster and native BSA. We have also studied their effect on the peak emission of BSA Au nanoclusters (650 nm). The photophysical characterization of a newly developed fluorophore in different environments is absolutely necessary to futher develop their biomedical and analytical applications. It was observed from our experiments that the tryptophan in BSA Au nanoclusters is better shielded from the polar environment. Tryptophan in native BSA showed a red shift in its peak emission wavelength position. Tryptophan is a highly polarity sensitive dye and a minimal change in its microenvironment can be easily observed in its photophysical properties. - Highlights: • Tryptophan is easily accessible in native BSA compared to BSA Au nanoclusters. • Guanidine HCL denatures native BSA more compared to BSA Au nanoclusters. • High temperature decreases the quantum yield of tryptophan and BSA Au nanocluster. • Emission wavelength of BSA Au nanoclusters remains constant with increasing pH. • BSA Au nanoclusters are robust to the changes in their environments.

Effect of quencher, denaturants, temperature and pH on the fluorescent properties of BSA protected gold nanoclusters

International Nuclear Information System (INIS)

Chib, Rahul; Butler, Susan; Raut, Sangram; Shah, Sunil; Borejdo, Julian; Gryczynski, Zygmunt; Gryczynski, Ignacy

2015-01-01

In this paper, we have synthesized BSA protected gold nanoclusters (BSA Au nanocluster) and studied the effect of quencher, protein denaturant, pH and temperature on the fluorescence properties of the tryptophan molecule of the BSA Au nanocluster and native BSA. We have also studied their effect on the peak emission of BSA Au nanoclusters (650 nm). The photophysical characterization of a newly developed fluorophore in different environments is absolutely necessary to futher develop their biomedical and analytical applications. It was observed from our experiments that the tryptophan in BSA Au nanoclusters is better shielded from the polar environment. Tryptophan in native BSA showed a red shift in its peak emission wavelength position. Tryptophan is a highly polarity sensitive dye and a minimal change in its microenvironment can be easily observed in its photophysical properties. - Highlights: • Tryptophan is easily accessible in native BSA compared to BSA Au nanoclusters. • Guanidine HCL denatures native BSA more compared to BSA Au nanoclusters. • High temperature decreases the quantum yield of tryptophan and BSA Au nanocluster. • Emission wavelength of BSA Au nanoclusters remains constant with increasing pH. • BSA Au nanoclusters are robust to the changes in their environments.

Inactivation kinetics of β-N-acetyl-D-glucosaminidase from green crab (Scylla serrata) by guanidinium chloride.

Science.gov (United States)

Zhang, Ji-Ping; Leng, Bo; Huang, Qian-Sheng; Yan, Ya-Wen; Liu, Xuan; Wang, Qin; Chen, Qing-Xi

2012-11-01

β-N-acetyl-D-glucosaminidase (NAGase) is a major member in chitinolytic enzymes system, which plays an important role in the hatching and molting processes of marine organism. The effects of guanidinium chloride (GuHCl) on the activity of NAGase from green crab (Scylla serrata) were investigated in this study. In results, GuHCl causes reversible inactivation of the enzyme at below 0.8 M concentrations, and the IC50 is estimated to be 0.15 M. The relationship between the enzyme activity and conformation was charaterized by monitoring the change of protein fluorescence spectra. With increasing GuHCl concentration, the fluorescence intensity of the enzyme distinctly decreases , and the maximal emission peaks appear red-shifted (from 338 nm to 343 nm). The enzyme inactivation precedes conformational changes, indicating that the enzyme active site is more flexible than the whole enzyme molecule. The result of the kinetics of inactivation shows that the value of k(+0) is larger than that of k(+0)'. It suggests that the substrate could protect the enzyme to a certain extent during guanidine denaturation. Our results provide important new insights in marine organism culture, especially in crustacean growth.

Comparative study of antioxidant, metal chelating and antiglycation activities of Momordica charantia flesh and pulp fractions.

Science.gov (United States)

Ghous, Tahseen; Aziz, Nouman; Mehmood, Zahid; Andleeb, Saiqa

2015-07-01

Momordica charantia is commonly used as a vegetable and folk medicine in most parts of South Asia. This study aims to determine and compare the antioxidant, metal chelating and antiglycation activities of aqueous extracts of M. charantia fruit flesh (MCF) and fruit pulp (MCP) fractions. Our results show that MCP has pronounced DPPH and ABTS radical scavenging potential compared to MCF. In the antiglycation assay both fractions illustrated considerable inhibitory activities against the formation of AGEs induced by glucose with an efficacy of 75 and 67% with 150 μl of MCP and MCF extracts respectively, almost equal to 0.3mM amino guanidine. Results for metal catalysed protein fragmentation and autoxidative and glycoxidation assays demonstrate that MCF and MCP inhibited metal catalysed protein fragmentation. The percentage of relative standard deviation for three replicate measurements of 150 μl of MCF and MCP was < 3.0% for antiglycation. The antioxidant assays with regression values of MCP (0.981 and 0.991) and MCF (0.967 and 0.999) were also recorded. We conclude that both extracts possess high antioxidant and antiglycation activities and are equally good sources of antioxidant and antiglycating agents.

Chaperonin GroE-facilitated refolding of disulfide-bonded and reduced Taka-amylase A from Aspergillus oryzae.

Science.gov (United States)

Kawata, Y; Hongo, K; Mizobata, T; Nagai, J

1998-12-01

The refolding characteristics of Taka-amylase A (TAA) from Aspergillus oryzae in the presence of the chaperonin GroE were studied in terms of activity and fluorescence. Disulfide-bonded (intact) TAA and non-disulfide-bonded (reduced) TAA were unfolded in guanidine hydrochloride and refolded by dilution into buffer containing GroE. The intermediates of both intact and reduced enzymes were trapped by GroEL in the absence of nucleotide. Upon addition of nucleotides such as ATP, ADP, CTP or UTP, the intermediates were released from GroEL and recovery of activity was detected. In both cases, the refolding yields in the presence of GroEL and ATP were higher than spontaneous recoveries. Fluorescence studies of intrinsic tryptophan and a hydrophobic probe, 8-anilinonaphthalene-1-sulfonate, suggested that the intermediates trapped by GroEL assumed conformations with different hydrophobic properties. The presence of protein disulfide isomerase or reduced and oxidized forms of glutathione in addition to GroE greatly enhanced the refolding reaction of reduced TAA. These findings suggest that GroE has an ability to recognize folding intermediates of TAA protein and facilitate refolding, regardless of the existence or absence of disulfide bonds in the protein.

Class I ADP-ribosylation factors are involved in enterovirus 71 replication.

Science.gov (United States)

Wang, Jianmin; Du, Jiang; Jin, Qi

2014-01-01

Enterovirus 71 is one of the major causative agents of hand, foot, and mouth disease in infants and children. Replication of enterovirus 71 depends on host cellular factors. The viral replication complex is formed in novel, cytoplasmic, vesicular compartments. It has not been elucidated which cellular pathways are hijacked by the virus to create these vesicles. Here, we investigated whether proteins associated with the cellular secretory pathway were involved in enterovirus 71 replication. We used a loss-of-function assay, based on small interfering RNA. We showed that enterovirus 71 RNA replication was dependent on the activity of Class I ADP-ribosylation factors. Simultaneous depletion of ADP-ribosylation factors 1 and 3, but not three others, inhibited viral replication in cells. We also demonstrated with various techniques that the brefeldin-A-sensitive guanidine nucleotide exchange factor, GBF1, was critically important for enterovirus 71 replication. Our results suggested that enterovirus 71 replication depended on GBF1-mediated activation of Class I ADP-ribosylation factors. These results revealed a connection between enterovirus 71 replication and the cellular secretory pathway; this pathway may represent a novel target for antiviral therapies.

GdnHCl-induced unfolding intermediate in the mitochondrial carbonic anhydrase VA.

Science.gov (United States)

Idrees, Danish; Prakash, Amresh; Haque, Md Anzarul; Islam, Asimul; Hassan, Md Imtaiyaz; Ahmad, Faizan

2016-10-01

Carbonic anhydrase VA (CAVA) is a mitochondrial enzyme belonging to the α-family of CAs, which is involved in several physiological processes including ureagenesis, lipogenesis, gluconeogenesis and neuronal transmission. Here, we have tried to understand the folding mechanism of CAVA using guanidine hydrochloride (GdnHCl)-induced denaturation at pH 8.0 and 25°C. The conformational stability was measured from the GdnHCl-induced denaturation study of CAVA monitored by circular dichroism (CD) and fluorescence measurements. On increasing the concentration of GdnHCl up to 5.0, a stable intermediate was observed between the concentrations 3.25M to 3.40M of the denaturant. However, CAVA gets completely denatured at 4.0M GdnHCl. The existence of a stable intermediate state was validated by 1-anilinonaphthalene-8-sulfonic acid (ANS binding) fluorescence and near-UV CD measurements. In silico studies were also performed to analyse the effect of GdnHCl on the structure and stability of CAVA under explicit conditions. Molecular dynamics simulations for 40ns were carried out and a well-defined correlation was established for both in vitro and in silico studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Avian influenza surveillance with FTA cards: field methods, biosafety, and transportation issues solved.

Science.gov (United States)

Kraus, Robert H S; van Hooft, Pim; Waldenström, Jonas; Latorre-Margalef, Neus; Ydenberg, Ronald C; Prins, Herbert H T

2011-08-02

Avian Influenza Viruses (AIVs) infect many mammals, including humans(1). These AIVs are diverse in their natural hosts, harboring almost all possible viral subtypes(2). Human pandemics of flu originally stem from AIVs(3). Many fatal human cases during the H5N1 outbreaks in recent years were reported. Lately, a new AIV related strain swept through the human population, causing the 'swine flu epidemic'(4). Although human trading and transportation activity seems to be responsible for the spread of highly pathogenic strains(5), dispersal can also partly be attributed to wild birds(6, 7). However, the actual reservoir of all AIV strains is wild birds. In reaction to this and in face of severe commercial losses in the poultry industry, large surveillance programs have been implemented globally to collect information on the ecology of AIVs, and to install early warning systems to detect certain highly pathogenic strains(8-12). Traditional virological methods require viruses to be intact and cultivated before analysis. This necessitates strict cold chains with deep freezers and heavy biosafety procedures to be in place during transport. Long-term surveillance is therefore usually restricted to a few field stations close to well equipped laboratories. Remote areas cannot be sampled unless logistically cumbersome procedures are implemented. These problems have been recognised(13, 14) and the use of alternative storage and transport strategies investigated (alcohols or guanidine)(15-17). Recently, Kraus et al.(18) introduced a method to collect, store and transport AIV samples, based on a special filter paper. FTA cards(19) preserve RNA on a dry storage basis(20) and render pathogens inactive upon contact(21). This study showed that FTA cards can be used to detect AIV RNA in reverse-transcription PCR and that the resulting cDNA could be sequenced and virus genes and determined. In the study of Kraus et al.(18) a laboratory isolate of AIV was used, and samples were handled

Preliminary Evaluation Of DWPF Impacts Of Boric Acid Use In Cesium Strip FOR SWPF And MCU

International Nuclear Information System (INIS)

Stone, M.

2010-01-01

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix, or the new suppressor, guanidine). Boric acid additions may lead to increased hydrogen generation during the SRAT and SME cycles as well as change the rheological properties of the feed. The boron in the strip effluent will impact glass composition and could require each SME batch to be trimmed with boric acid to account for any changes in the boron from strip effluent additions. Addition of boron with the strip effluent will require changes in the frit composition and could lead to changes in melt behavior. The severity of the impacts from the boric acid additions is dependent on the amount of boric acid added by the strip effluent. The use of 0.1M or higher concentrations of boric acid in the strip effluent was found to significantly impact DWPF operations while the impact of 0.01M boric acid is expected to be relatively minor. Experimental testing is required to resolve the issues identified during the preliminary evaluation. The issues to be addressed by the testing are: (1) Impact on SRAT acid addition and hydrogen generation; (2) Impact on melter feed rheology; (3) Impact on glass composition control; (4) Impact on frit production; and (5) Impact on melter offgas. A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the

Comparison of the carcinogenic effectiveness in mouse skin of methyl- and ethylnitrosourea, nitrosourethane and nitrosonitro-guanidine and the effect of deuterium labeling

International Nuclear Information System (INIS)

Lijinsky, W.

1982-01-01

The carcinogenic activities of a number of directly acting methylating and ethylating agents have been compared by mouse skin painting in acetone solution. Nitrosomethylurethane and nitrosoethylurethane failed to induce tumors after greater than 60 weeks treatment. Nitrosomethylurea was somewhat more effective than nitrosoethylurea, as measured by the longer latent period than nitrosoethylurea, as measured Nitrosomethylnitroguanidine, by the same measure, was a weaker carcinogen than nitrosoethylnitroguanidine at both dose levels used (0.02 M and 0.008 M); the latter compound was the most potent skin carcinogen of those examined. There was no significant difference in carcinogenic effectiveness when the alkyl group of the nitrosoureas or the nitronitrosoguanidines contained deuterium instead of hydrogen, which supports the concept that alkylation of cellular macromolecules by the intact alkyl group is responsible for carcinogenesis by these compounds

Formation of protein/surfactant adsorption layer at the air/water interface as studied by dilational surface rheology.

Science.gov (United States)

Mikhailovskaya, A A; Noskov, B A; Lin, S-Y; Loglio, G; Miller, R

2011-08-25

The dynamic dilatational surface elasticity of mixed solutions of globular proteins (β-lactoglobulin (BLG) and bovine serum albumin (BSA)) with cationic (dodecyltrimethylammonium bromide (DTAB)) and anionic (sodium dodecyl sulfate (SDS)) surfactants was measured as a function of the surfactant concentration and surface age. If the cationic surfactant concentration exceeds a certain critical value, the kinetic dependencies of the dynamic surface elasticity of BLG/DTAB and BSA/DTAB solutions become nonmonotonous and resemble those of mixed solutions of proteins with guanidine hydrochloride. This result indicates not only the destruction of the protein tertiary structure in the surface layer of mixed solution but also a strong perturbation of the secondary structure. The corresponding kinetic dependencies for protein solutions with added anionic surfactants are always monotonous, thereby revealing a different mechanism of the adsorption layer formation. One can assume that the secondary structure is destroyed to a lesser extent in the latter case and hinders the formation of loops and tails at the interface. The increase of the solution's ionic strength by the addition of sodium chloride results in stronger changes of the protein conformations in the surface layer and the appearance of a local maximum in the kinetic dependencies of the dynamic surface elasticity in a relatively narrow range of SDS concentration. © 2011 American Chemical Society

Microsystem to evaluate the incorporation of 3H-uridine in macrophage RNA

International Nuclear Information System (INIS)

Varesio, L.; Naglich, J.; Brunda, M.J.; Taramelli, D.; Eva, A.

1981-01-01

A method is described for the evaluation of the total 3H-uridine incorporated by macrophages in vitro into trichloroacetic acid (TCA)-precipitable material. The technique is based upon solubilization of the macrophage monolayers by guanidine-HC1, followed by TCA precipitation. The recovery of RNA into the precipitate and the reproducibility of the results were strictly dependent on the use of filtered reagents and on incubation of the TCA precipitate for 2 or more hours at 4 degree C before harvesting. Treatment with quanidine-HC1 did not affect the recovery of labeled RNA. Moreover, we observed that radioactive precipitate had the characteristics of RNA, since its recovery was sensitive to the addition of unlabeled uridine in the culture medium and to the treatment of the macrophages with inhibitors of RNA synthesis, but not of protein synthesis. Tritiated uridine incorporation in microcultures of macrophages can be assessed with this technique, by processing the cells directly in the wells. The main advantages of this procedure are: 1) the radioactivity can be measured by semiautomatic cell harvesters, 2) a small number of macrophages are required, and 3) many samples can be processed simultaneously. Overall, the technique is simple, rapid, and could be successfully adapted to study other metabolic pathways

Optimization of expression and purification of human mortalin (Hsp70): Folding/unfolding analysis

Science.gov (United States)

Khan, Mohd Shahnawaz; Ahmed, Anwar; Tabrez, Shams; Islam, Badar ul; Rabbani, Nayyar; Malik, Ajamaluddin; Ismael, Mohamad A.; Alsenaidy, Mohammad A.; Alsenaidy, Abdulrahman M.

2017-12-01

Human mortalin is a Hsp70 mitochondrial protein that plays an essential role in the biogenesis of mitochondria. The deregulation of mortalin expression and its functions could lead to several age-associated disorders and some types of cancers. In the present study, we optimized the expression and purification of recombinant human mortalin by the use of two-step chromatography. Low temperature (18 °C) and 0.5 mM (IPTG) was required for optimum mortalin expression. Chaperone activity of mortalin was assessed by the citrate synthase and insulin protection assay, which suggested their protective role in mitochondria. Folding and unfolding assessments of mortalin were carried out in the presence of guanidine hydrochloride (GdnHCl) by intrinsic fluorescence measurement, ANS (8-analino 1-nephthlene sulfonic acid) binding and CD (circular dichroism) analysis. Under denaturing conditions, mortalin showed decrease in tryptophan fluorescence intensity along with a red shift of 11 nm. Moreover, ANS binding studies illustrated decrease in hydrophobicity. CD measurement of mortalin showed a predominant helical structure. However, the secondary structure was lost at low concentration of GdnHCl (1 M). We present a simple and robust method to produce soluble mortalin and warranted that chaperones are also susceptible to unfolding and futile to maintain protein homeostasis.

Acute cardiovascular toxicity of sterilizers, PHMG, and PGH: severe inflammation in human cells and heart failure in zebrafish.

Science.gov (United States)

Kim, Jae-Yong; Kim, Hak Hyeon; Cho, Kyung-Hyun

2013-06-01

In 2011, dozens of children and pregnant women in Korea died by exposure to sterilizer for household humidifier, such as Oxy(®) and Cefu(®). Until now, however, it remains unknown how the sterilizer affect the human health to cause the acute deaths. To find its toxicity for organ, we investigated the putative toxicity of the sterilizer in the cardiovascular system. The sterilizers, polyhexamethylene guanidine phosphate (PHMG, Cefu(®)), and oligo-[2-(2-ethoxy)-ethoxyethyl)-guanidinium-chloride (PGH, Oxy(®)) were treated to human lipoproteins, macrophages, and dermal fibroblast cells. The PGH and PHMG at normal dosages caused severe atherogenic process in human macrophages, cytotoxic effect, and aging in human dermal cell. Zebrafish embryos, which were exposed to the sterilizer, showed early death with acute inflammation and attenuated developmental speed. All zebrafish exposed to the working concentration of PHMG (final 0.3 %) and PGH (final 10 mM) died within 70 min and displayed acute increases in serum triacylglycerol level and fatty liver induction. The dead zebrafish showed severe accumulation of fibrous collagen in the bulbous artery of the heart with elevation of reactive oxygen species. In conclusion, the sterilizers showed acute toxic effect in blood circulation system, causing by severe inflammation, atherogenesis, and aging, with embryo toxicity.

Antibacterial performance of polypropylene nonwoven fabric wound dressing surfaces containing passive and active components

International Nuclear Information System (INIS)

Xin, Zhirong; Du, Shanshan; Zhao, Chunyu; Chen, Hao; Sun, Miao; Yan, Shunjie; Luan, Shifang; Yin, Jinghua

2016-01-01

Graphical abstract: - Highlights: • PNVP and PHMG components were covalently immobilized on PP_N_W_F surface. • PP_N_W_F-g-PNVP-PHMG possessed bacterial adhesion-resistant and bactericidal capabilities. • PP_N_W_F-g-PNVP-PHMG obviously suppressed platelet and red blood cell adhesion. - Abstract: A growing number of wound dressing-related nosocomial infections necessitate the development of novel antibacterial strategies. Herein, polypropylene non-woven fabric (PP_N_W_F) was facilely modified with passive and active antibacterial components, namely photografting polymerization both N-Vinyl-2-pyrrolidone (NVP) and glycidyl methacrylate (GMA) monomers, and the introduction of guanidine polymer through the reaction between active amino groups and epoxy groups. The modified samples were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), respectively. Water contact angle measurement, antibacterial test, platelet and red blood cell adhesion were used to evaluate the hydrophilicity, antibacterial properties and hemocompatibility of the samples. It was found that the antibacterial properties were obviously enhanced, meanwhile significantly suppressing platelet and red blood cell adhesion after the above modification. This PP_N_W_F samples that possess antifouling and antimicrobial properties, have great potential in wound dressing applications.

Synthesis, anti-inflammatory, analgesic and anticonvulsant activities of some new 4,6-dimethoxy-5-(heterocyclesbenzofuran starting from naturally occurring visnagin

Directory of Open Access Journals (Sweden)

E.R. El-Sawy

2014-12-01

Full Text Available Novel 3-(4,6-dimethoxybenzofuran-5-yl-1-phenyl-1H-pyrazole-4-carboxaldehyde (3 and 3-chloro-3-(4,6-dimethoxybenzofuran-5-ylpropenal (4 were prepared via Vilsmeier–Haack reaction of 1-(4,6-dimethoxybenzofuran-5-ylethanone (1 and its hydrazone derivative 2. Reaction of compound 4 with some hydrazine derivatives, namely hydrazine hydrate, phenylhydrazine and benzylhydrazine hydrochloride led to the formation of pyrazole derivatives 5–8, respectively. On the other hand, reaction of compound 4 with thiourea, urea or guanidine gave the pyrimidine derivatives 9–11, respectively. Reaction of amino compound 11 with acetic anhydride, benzoyl chloride and benzenesulphonyl chloride yielded N-substituted pyrimidine derivatives 12–14, respectively. Reaction of diazonium salt of compound 11 with sodium azide afforded azidopyrimidine derivative 15, which upon reaction with ethyl acetoacetate gave 1,2,3-triazole derivative 16. Acid catalyzed reaction of 11 with p-nitrobenzaldehyde gave Schiff base 17, which cyclized upon reaction with thioglycolic acid or chloroacetyl chloride to give thiazolidin-4-one 18 and azetidin-2-one 19, respectively. The newly synthesized compounds were tested for their anti-inflammatory, analgesic and anticonvulsant activities. Depending on the obtained results, the newly synthesized compounds possess significant anti-inflammatory, analgesic and anticonvulsant activities.

Improved Gas Chromatographic Determination of Guanidino Compounds Using Isovaleroylacetone and Ethyl Chloroformate as Derivatizing Reagents.

Science.gov (United States)

Zounr, Rizwan Ali; Khuhawar, Mumammad Yar; Jahangir, Taj Muhammad; Alamgir, Malik

2016-01-01

An improved GC method in terms of sensitivity and decrease in the analysis time has been developed for the analysis of eight guanidino compounds: guanidine (G), methylguanidine (MG), creatinine (CTN), guanidinoacetic acid (GAA), guanidinobutyric acid (GBA), guanidinopropionic acid (GPA), argenine (Arg), and guanidinosuccinic acid (GSA), using isovaleroylacetone (IVA) and ethyl chloroformate (ECF) as derivatizing reagents. The separation was obtained from column HP-5 (30 m × 0.32 mm i.d.) with film thickness of 0.25 μm within 11 min. The linear calibrations were obtained with 0.5 to 50 μg/mL with coefficient of determination (R(2)) within 0.9969 - 0.9998. Limits of detections (LODs) were within 5 - 140 ng/mL. The derivatization, separation and determination was repeatable (n = 6) with relative standard deviation (RSD) within 1.2 - 3.1%. The guanidino compounds were determined in deproteinized serum of healthy volunteers and uremic patients within below LOD to 8.8 μg/mL and below LOD to 43.99 μg/mL with RSD within 1.4 - 3.6%. The recovery of guanidino compounds calculated by standard addition from serum was within 96.1 - 98.9%, with RSD 1.4 - 3.6%.

Effective electrochemical method for investigation of hemoglobin unfolding based on the redox property of heme groups at glassy carbon electrodes.

Science.gov (United States)

Li, Xianchan; Zheng, Wei; Zhang, Limin; Yu, Ping; Lin, Yuqing; Su, Lei; Mao, Lanqun

2009-10-15

This study demonstrates a facile and effective electrochemical method for investigation of hemoglobin (Hb) unfolding based on the electrochemical redox property of heme groups in Hb at bare glassy carbon (GC) electrodes. In the native state, the heme groups are deeply buried in the hydrophobic pockets of Hb with a five-coordinate high-spin complex and thus show a poor electrochemical property at bare GC electrodes. Upon the unfolding of Hb induced by the denaturant of guanidine hydrochloride (GdnHCl), the fifth coordinative bond between the heme groups and the residue of the polypeptides (His-F8) is broken, and as a result, the heme groups initially buried deeply in the hydrophobic pockets dissociate from the polypeptide chains and are reduced electrochemically at GC electrodes, which can be used to probe the unfolding of Hb. The results on the GdnHCl-induced Hb unfolding obtained with the electrochemical method described here well coincide with those studied with other methods, such as UV-vis spectroscopy, fluorescence, and circular dichroism. The application of the as-established electrochemical method is illustrated to study the kinetics of GdnHCl-induced Hb unfolding, the GdnHCl-induced unfolding of another kind of hemoprotein, catalase, and the pH-induced Hb unfolding/refolding.

Editorial, Vol. 3, issue 1 (2016: Submissions between August, 2015 – February, 2016

Directory of Open Access Journals (Sweden)

Hasan KÜÇÜKBAY

2017-06-01

Full Text Available Hello and welcome to our journal, which encompasses all chemical sub-disciplines and distributes, free of charge, with an open-access approach throughout the world. We hope that you will like the contributions.In this issue, we published a research article from Nigeria about insect repellent property of an essential oil. Another article was a review sent from Libya to our editorial office about electrochemical methods used in the treatment of nuclear wastes. The third article is from Iran, about obtaining guanidines with the reaction of carbodiimides in the presence of ionic liquid, an important topic for over a decade. The last article went to our office from Egypt and about synthesis of quinoline ketones from a variety of heterocycles.We would very much like to receive your submissions as well; to gain more information, browse to the website of our journal at http://dergipark.ulakbim.gov.tr/jotcsa and send an e-mail to our managing editor, Mr. Barbaros AKKURT, at jotcsa@turchemsoc.org or myself at hasan.kucukbay@inonu.edu.tr.Goodbye, and let us meet in August with our new issue...Best regards,Prof. Dr. Hasan KÜÇÜKBAY, PhDEditor-in-chief, JOTCSA

Minimizing technical variation during sample preparation prior to label-free quantitative mass spectrometry.

Science.gov (United States)

Scheerlinck, E; Dhaenens, M; Van Soom, A; Peelman, L; De Sutter, P; Van Steendam, K; Deforce, D

2015-12-01

Sample preparation is the crucial starting point to obtain high-quality mass spectrometry data and can be divided into two main steps in a bottom-up proteomics approach: cell/tissue lysis with or without detergents and a(n) (in-solution) digest comprising denaturation, reduction, alkylation, and digesting of the proteins. Here, some important considerations, among others, are that the reagents used for sample preparation can inhibit the digestion enzyme (e.g., 0.1% sodium dodecyl sulfate [SDS] and 0.5 M guanidine HCl), give rise to ion suppression (e.g., polyethylene glycol [PEG]), be incompatible with liquid chromatography-tandem mass spectrometry (LC-MS/MS) (e.g., SDS), and can induce additional modifications (e.g., urea). Taken together, all of these irreproducible effects are gradually becoming a problem when label-free quantitation of the samples is envisioned such as during the increasingly popular high-definition mass spectrometry (HDMS(E)) and sequential window acquisition of all theoretical fragment ion spectra (SWATH) data-independent acquisition strategies. Here, we describe the detailed validation of a reproducible method with sufficient protein yield for sample preparation without any known LC-MS/MS interfering substances by using 1% sodium deoxycholate (SDC) during both cell lysis and in-solution digest. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Risk assessment and monitoring of dinotefuran and its metabolites for Chinese consumption of apples.

Science.gov (United States)

Yu, Weiwei; Huang, Min; Chen, Jiaojiao; Wu, Sizhuo; Zheng, Kunming; Zeng, Song; Zhang, Kankan; Hu, Deyu

2017-09-26

Residues of dinotefuran and its metabolites, 1-methyl-3-(tetrahydro-3-furylmethyl)urea (UF) and 1-methyl-3-(tetrahydro-3-furylmethyl)guanidine (DN), in apple were investigated using a "QuEChERS" (quick, easy, cheap, effective, rugged, safe) pretreatment and liquid chromatography-tandem mass spectrometry. Limits of detection (LODs) and quantification (LOQs) of dinotefuran, UF, and DN in apples were 0.011-0.960 and 0.037-3.200 μg/kg, respectively. The average recoveries of dinotefuran, UF, and DN in apple ranged from 70.0 to 83.6% with relative standard deviations less than 13%. A formulation of 20% water-dispersible dinotefuran granules was sprayed at 1-1.5-fold the recommended dose 3-4 times on apple trees. Total terminal residues of dinotefuran in apple were less than 2 mg/kg, which is the maximum residue limit (MRL) set by Japan. When following the recommended application guidelines, dinotefuran is unlikely to present significant health concerns to the Chinese population because the risk quotient (RQ) is less than 100%. This work could provide guidance for the safe use of dinotefuran and serve as a reference for the establishment of a maximum residue limit of dinotefuran in apple in China.

Caseins from bovine colostrum and milk strongly bind piscidin-1, an antimicrobial peptide from fish.

Science.gov (United States)

Kütt, Mary-Liis; Stagsted, Jan

2014-09-01

A model system of bovine colostrum and piscidin, a fish-derived antimicrobial peptide, was developed to study potential interactions of antimicrobial peptides in colostrum. We did not detect any antimicrobial activity of colostrum using the radial plate diffusion assay; in fact colostrum completely abrogated activity of added piscidin. This could not be explained by degradation of piscidin by colostrum, which was less than ten percent. We found that colostrum even protected piscidin against degradation by added proteases. We further observed that colostrum and milk rapidly quenched the fluorescence of fluorescein-piscidin but not that of fluorescein. This effect was not seen with BSA and the specific quenching of fluorescein-piscidin by colostrum was saturably inhibited with unlabeled piscidin. Size exclusion chromatography indicated that fluorescein-piscidin bound to casein micelles with no apparent binding to IgG or whey proteins. Further, addition of pure caseins was able to quench fluorescence of fluorescein-piscidin and to inhibit the antimicrobial activity of piscidin. The interaction between caseins and piscidin could be dissociated by guanidine hydrochloride and recovered piscidin had antimicrobial activity against bacteria. Based on our results we propose that caseins could be carriers for antimicrobial peptides in colostrum and milk. Copyright © 2014 Elsevier B.V. All rights reserved.

An analytical method for estimating the ¹⁴N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

Energy Technology Data Exchange (ETDEWEB)

Iselin, Louis Henry [Univ. of Florida, Gainesville, FL (United States)

1992-01-01

The use of ¹⁴N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing ¹⁴N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The ¹⁴N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

Scaffold expulsion and genome packaging trigger stabilization of herpes simplex virus capsids

Science.gov (United States)

Roos, Wouter H.; Radtke, Kerstin; Kniesmeijer, Edward; Geertsema, Hylkje; Sodeik, Beate; Wuite, Gijs J. L.

2009-01-01

Herpes simplex virus type 1 (HSV1) capsids undergo extensive structural changes during maturation and DNA packaging. As a result, they become more stable and competent for nuclear egress. To further elucidate this stabilization process, we used biochemical and nanoindentation approaches to analyze the structural and mechanical properties of scaffold-containing (B), empty (A), and DNA-containing (C) nuclear capsids. Atomic force microscopy experiments revealed that A and C capsids were mechanically indistinguishable, indicating that the presence of DNA does not account for changes in mechanical properties during capsid maturation. Despite having the same rigidity, the scaffold-containing B capsids broke at significantly lower forces than A and C capsids. An extraction of pentons with guanidine hydrochloride (GuHCl) increased the flexibility of all capsids. Surprisingly, the breaking forces of the modified A and C capsids dropped to similar values as those of the GuHCl-treated B capsids, indicating that mechanical reinforcement occurs at the vertices. Nonetheless, it also showed that HSV1 capsids possess a remarkable structural integrity that was preserved after removal of pentons. We suggest that HSV1 capsids are stabilized after removal of the scaffold proteins, and that this stabilization is triggered by the packaging of DNA, but independent of the actual presence of DNA. PMID:19487681

Poly(amido-amine)-based hydrogels with tailored mechanical properties and degradation rates for tissue engineering.

Science.gov (United States)

Martello, Federico; Tocchio, Alessandro; Tamplenizza, Margherita; Gerges, Irini; Pistis, Valentina; Recenti, Rossella; Bortolin, Monica; Del Fabbro, Massimo; Argentiere, Simona; Milani, Paolo; Lenardi, Cristina

2014-03-01

Poly(amido-amine) (PAA) hydrogels containing the 2,2-bisacrylamidoacetic acid-4-amminobutyl guanidine monomeric unit have a known ability to enhance cellular adhesion by interacting with the arginin-glycin-aspartic acid (RGD)-binding αVβ3 integrin, expressed by a wide number of cell types. Scientific interest in this class of materials has traditionally been hampered by their poor mechanical properties and restricted range of degradation rate. Here we present the design of novel biocompatible, RGD-mimic PAA-based hydrogels with wide and tunable degradation rates as well as improved mechanical and biological properties for biomedical applications. This is achieved by radical polymerization of acrylamide-terminated PAA oligomers in both the presence and absence of 2-hydroxyethylmethacrylate. The degradation rate is found to be precisely tunable by adjusting the PAA oligomer molecular weight and acrylic co-monomer concentration in the starting reaction mixture. Cell adhesion and proliferation tests on Madin-Darby canine kidney epithelial cells show that PAA-based hydrogels have the capacity to promote cell adhesion up to 200% compared to the control. Mechanical tests show higher compressive strength of acrylic chain containing hydrogels compared to traditional PAA hydrogels. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Creatine supplementation reduces sleep need and homeostatic sleep pressure in rats.

Science.gov (United States)

Dworak, Markus; Kim, Tae; Mccarley, Robert W; Basheer, Radhika

2017-06-01

Sleep has been postulated to promote brain energy restoration. It is as yet unknown if increasing the energy availability within the brain reduces sleep need. The guanidine amino acid creatine (Cr) is a well-known energy booster in cellular energy homeostasis. Oral Cr-monohydrate supplementation (CS) increases exercise performance and has been shown to have substantial effects on cognitive performance, neuroprotection and circadian rhythms. The effect of CS on cellular high-energy molecules and sleep-wake behaviour is unclear. Here, we examined the sleep-wake behaviour and brain energy metabolism before and after 4-week-long oral administration of CS in the rat. CS decreased total sleep time and non-rapid eye movement (NREM) sleep significantly during the light (inactive) but not during the dark (active) period. NREM sleep and NREM delta activity were decreased significantly in CS rats after 6 h of sleep deprivation. Biochemical analysis of brain energy metabolites showed a tendency to increase in phosphocreatine after CS, while cellular adenosine triphosphate (ATP) level decreased. Microdialysis analysis showed that the sleep deprivation-induced increase in extracellular adenosine was attenuated after CS. These results suggest that CS reduces sleep need and homeostatic sleep pressure in rats, thereby indicating its potential in the treatment of sleep-related disorders. © 2017 European Sleep Research Society.

123I-β-methyl-iodophenyl-pentadecanoic acid myocardial scintigraphy in diabetic patients without overt ischemic heart disease

International Nuclear Information System (INIS)

Shinmura, Ken; Tani, Masato; Suganuma, Yukako; Hasegawa, Hiroshi; Kawamura, Masatoshi; Nakamura, Yoshiro; Hashimoto, Jun; Kubo, Atsushi

1995-01-01

We evaluated 123 I-β-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial scintigraphy in 15 diabetes mellitus patients without overt coronary heart disease. Patients with overt coronary heart disease were excluded by careful history taking, resting electrocardiography, treadmill exercise testing echocardiography and resting 201 Tl scintigraphy. Patients with remarkably impaired left ventricular (LV) systolic function (%FS 2 , FBS: 178 vs 114 mg/dl, HbA1c: 7.6 vs 6.2%, IRI: 18.5 vs 9.5 μU/ml, LVEDD: 52 vs 44 mm). 123 I-metaiodobenzyl-guanidine (MIBG) scintigraphy in the 5 patients with abnormal BMIPP uptake showed more severe defects than in the 10 patients with normal BMIPP imaging. BMIPP scintigraphy demonstrated a significant correlation between H/M and L/M by BMIPP (r=0.74). Correlation between H/M by BMIPP scintigraphy and clinical parameters (BMI, systolic blood pressure, FBS, HbA1c, IRI) were found, suggesting that diabetes mellitus patients without over coronary heart disease show abnormal BMIPP imaging when their general glucose utility and 123 I-MIBG uptake are severely impaired (progression of insulin resistance and sympathetic nerve involvement). BMIPP scintigraphy may be useful in investigating the pathogenesis and subclinical abnormality of diabetic heart. (J.P.N.)

Agmatine enhances antidepressant potency of MK-801 and conventional antidepressants in mice.

Science.gov (United States)

Neis, Vivian Binder; Moretti, Morgana; Manosso, Luana Meller; Lopes, Mark W; Leal, Rodrigo Bainy; Rodrigues, Ana Lúcia S

2015-03-01

Agmatine, an endogenous guanidine amine, has been shown to produce antidepressant-like effects in animal studies. This study investigated the effects of the combined administration of agmatine with either conventional monoaminergic antidepressants or the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 in the tail suspension test (TST) in mice. The aim was to evaluate the extent of the antidepressant synergism by examining the ability of a fixed dose of agmatine to shift the antidepressant potency of fluoxetine, imipramine, bupropion and MK-801. A sub-effective dose of agmatine (0.0001 mg/kg, p.o.) significantly increased the potency by which fluoxetine, imipramine, bupropion and MK-801 decreased immobility time in the TST by 2-fold (fluoxetine), 10-fold (imipramine and bupropion) and 100-fold (MK-801). Combined with previous evidence indicating a role of monoaminergic systems in the effect of agmatine, the current data suggest that agmatine may modulate monoaminergic neurotransmission and augment the activity of conventional antidepressants. Moreover, this study found that agmatine substantially augmented the antidepressant-like effect of MK-801, reinforcing the notion that this compound modulates NMDA receptor activation. These preclinical data may stimulate future clinical studies testing the effects of augmentation therapy with agmatine for the management of depressive disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

Enhanced production of bacitracin by a mutant strain bacillus licheniformis UV-MN-HN-8 (enhanced bacitracin production by mutagenesis)

International Nuclear Information System (INIS)

Aftab, M.N.; Ikram-ul-Haq; Baig, S.

2010-01-01

The present study is focused on the improvement of Bacillus licheniformis through random mutagenesis to obtain mutant having enhanced production of bacitracin. Many isolates of Bacillus licheniformis were isolated and the isolate GP-40 produced maximum bacitracin production (16 +- 0.72 IU/mL). Treatment of Bacillus licheniformis GP-40 with ultraviolet (UV) radiations increased bacitracin production to 29 +- 0.69 IU/mL. Similarly, treatment of vegetative cells of GP-40 with chemicals like N-methyl N'-nitro N-nitroso guanidine (MNNG) and Nitrous acid (HNO/sub 2/) increased bacitracin production to 35 +- 1.35 IU/mL and 29 +- 0.89 IU/mL respectively. Studies regarding the combined effect of UV and chemical treatment on parental cells exhibited significantly higher titers of bacitracin with maximum bacitracin production reached to 47.6 +- 0.92 IU/mL. An increase of 2.97 fold production of bacitracin in comparison to wild type was observed. Mutant strain was highly stable and produced consistent yield of bacitracin even after 15 generations. On the basis of kinetic variables, notably mu (h-/sup 1/)max, Yp/x, qp, Qp and Qx mutant strain B. licheniformis UV-MN-HN-8 was found to be a hyper producer of bacitracin. (author)

Synthesis of positively charged hybrid PHMB-stabilized silver nanoparticles: the search for a new type of active substances used in plant protection products

Science.gov (United States)

Krutyakov, Yurii A.; Kudrinsky, Alexey A.; Gusev, Alexander A.; Zakharova, Olga V.; Klimov, Alexey I.; Yapryntsev, Alexey D.; Zherebin, Pavel M.; Shapoval, Olga A.; Lisichkin, Georgii V.

2017-07-01

Modern agriculture calls for a decrease in pesticide application, particularly in order to decrease the negative impact on the environment. Therefore the development of new active substances and plant protection products (PPP) to minimize the chemical load on ecosystems is a very important problem. Substances based on silver nanoparticles are a promising solution of this problem because of the fact that in correct doses such products significantly increase yields and decrease crop diseases while displaying low toxicity to humans and animals. In this paper we for the first time propose application of polymeric guanidine compounds with varying chain lengths (from 10 to 130 elementary links) for the design and synthesis of modified silver nanoparticles to be used as the basis of a new generation of PPP. Colloidal solutions of nanocrystalline silver containing 0.5 g l-1 of silver and 0.01-0.4 g l-1 of polyhexamethylene biguanide hydrochloride (PHMB) were obtained by reduction of silver nitrate with sodium borohydride in the presence of PHMB. The field experiment has shown that silver-containing solutions have a positive effect on agronomic properties of potato, wheat and apple. Also the increase in activity of such antioxidant system enzymes as peroxidase and catalase in the tissues of plants treated with nanosilver has been registered.

Structure of a retro-binding peptide inhibitor complexed with human alpha-thrombin.

Science.gov (United States)

Tabernero, L; Chang, C Y; Ohringer, S L; Lau, W F; Iwanowicz, E J; Han, W C; Wang, T C; Seiler, S M; Roberts, D G; Sack, J S

1995-02-10

The crystallographic structure of the ternary complex between human alpha-thrombin, hirugen and the peptidyl inhibitor Phe-alloThr-Phe-O-CH3, which is acylated at its N terminus with 4-guanidino butanoic acid (BMS-183507), has been determined at 2.6 A resolution. The structure reveals a unique "retro-binding" mode for this tripeptide active site inhibitor. The inhibitor binds with its alkyl-guanidine moiety in the primary specificity pocket and its two phenyl rings occupying the hydrophobic proximal and distal pockets of the thrombin active site. In this arrangement the backbone of the tripeptide forms a parallel beta-strand to the thrombin main-chain at the binding site. This is opposite to the orientation of the natural substrate, fibrinogen, and all the small active site-directed thrombin inhibitors whose bound structures have been previously reported. BMS-183507 is the first synthetic inhibitor proved to bind in a retro-binding fashion to thrombin, in a fashion similar to that of the N-terminal residues of the natural inhibitor hirudin. Furthermore, this new potent thrombin inhibitor (Ki = 17.2 nM) is selective for thrombin over other serine proteases tested and may be a template to be considered in designing hirudin-based thrombin inhibitors with interactions at the specificity pocket.

Synthesis of some pyridine and pyrimidine derivatives via Michael-Addition

International Nuclear Information System (INIS)

El-Baih, Fatma E.M.; Al-Rasheed, Hessa H.; Al-Hazimi, Hassan M.

2006-01-01

Synthesis of pyridine and pyrimidine analogues 4 and 6-9 were achieved by Michael-addition of compounds containing either active methylene groups like, malononitrile , ethyl cyanoacetate and 1-tetralone or compounds containing active hydrogen atoms like, guanidine in the presence of an oxidizing agent and thiourea to 2-arylmethylidine-1-tetralone and 2-arylmethylidine-6-methoxy-1-tetralone (2) (enones). Addition of malononitrile in piperidine at room temperature to 2-amino-3-cyno-naphtho [1, 2-malonoitrile in sodium alkoxide or sodium hydroxide to 2 gave 4. Cyclization of 3a with acetic anhydride in the presence of conc. H2sO4 gave the naphtha-pyrano[2, 3-d]pyrimidin-8-one (5). Condensation of the pyrimidine thione derivatives 9 with chloroacetic acid gave the 3-oxobenzo[h]thiazoladino[2, 3-b]quinazoline derivatives (10), which were reacted through their active methylene groups with aromatic aldehydes to give the arylidine derivatives 11. These compounds were also prepared in one step by reacting 9 with chloroacetic acid and aromatic aldehydes. Condensation of 9 with 3-bromopropanoic acid gave 4-oxo-benzo[h]1, 3-thiazino[2, 3-b]quinazoline derivatives (12). The structures of the prepared compounds were mainly confirmed on the basis of spectroscopic methods. (author)

The conformational stability and flexibility of insulin with an additional intramolecular cross-link

International Nuclear Information System (INIS)

Brems, D.N.; Brown, P.L.; Nakagawa, S.H.; Tager, H.S.

1991-01-01

The conformational stability and flexibility of insulin containing a cross-link between the alpha-amino group of the A-chain to the epsilon-amino group of Lys29 of the B-chain was examined. The cross-link varied in length from 2 to 12 carbon atoms. The conformational stability was determined by guanidine hydrochloride-induced equilibrium denaturation and flexibility was assessed by H2O/D2O amide exchange. The cross-link has substantial effects on both conformational stability and flexibility which depend on its length. In general, the addition of a cross-link enhances conformational stability and decreases flexibility. The optimal length for enhanced stability and decreased flexibility was the 6-carbon link. For the 6-carbon link the Gibbs free energy of unfolding was 8.0 kcal/mol compared to 4.5 kcal/mol for insulin, and the amide exchange rate decreased by at least 3-fold. A very short cross-link (i.e. the 2-carbon link) caused conformational strain that was detectable by a lack of stabilization in the Gibbs free energy of unfolding and enhancement in the amide exchange rate compared to insulin. The effect of the cross-link length on insulin hydrodynamic properties is discussed relative to previously obtained receptor binding results

Polymerase chain reaction for the diagnosis of bovine genital campylobacteriosis Reação em cadeia da polimerase para o diagnóstico de campilobacteriose genital bovina

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Ana C.M. Groff

2010-12-01

Full Text Available Bovine genital campylobacteriosis is a common venereal disease of cattle; the prevalence of this disease can be underestimated mostly because of the nature of the etiological agent, the microaerobic Campylobacter fetus subspecies venerealis. The purpose of the current study was to evaluate the utilization of polymerase chain reaction (PCR in the diagnosis of genital campylobacteriosis in samples obtained from bull prepuce aspirate, cow cervical mucus, and abomasum contents of aborted fetuses, collected into enrichment medium. Five different DNA extraction protocols were tested: thermal extraction, lysis with proteinase K, lysis with guanidine isothiocyanate, lysis with DNAzol, and lysis with hexadecyltrimethylammonium bromide (CTAB. The specificity, sensitivity, and technical application of the PCR assay were also evaluated with clinical samples and compared to bacterial isolation by standard culture. DNA extraction by the CTAB protocol provided better results in PCR, and it was able to detect 63 colony-forming units per ml of C. fetus. Out of 277 clinical samples tested, 68 (24% were positive for Campylobacter fetus using PCR, while only 8 (2.8% of the samples were positive by bacterial isolation in solid medium, proving the superiority of the PCR technique when compared to the standard isolation method, and providing evidence for its usefulness as a better screening test in cattle for the diagnosis of bovine genital campylobacteriosis.Campilobacteriose genital bovina é uma doença venérea comum em bovinos. A prevalência desta doença pode ser subestimada na maioria das vezes pela natureza microaeróbica do agente etiológico, Campylobacter fetus subspecies venerealis. O propósito do presente estudo foi avaliar a utilização da reação de polimerase em cadeia (PCR no diagnóstico de campilobacteriose genital em amostras obtidas de aspirado prepucial de touros, muco cervical de vacas e conteúdo abomasal de fetos abortados, coletados em

Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis

Energy Technology Data Exchange (ETDEWEB)

Li, Shou-lin; Ikeda, Jun; Takita, Tamotsu; Sekiguchi, Yohei; Demachi, Jun; Chikama, Hisao; Goto, Atsushi; Shirato, Kunio [Tohoku Univ., Sendai (Japan). School of Medicine

1998-11-01

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine ({sup 123}I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of {sup 123}I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of {sup 123}I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). {sup 123}I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of {sup 123}I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the {sup 123}I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis

International Nuclear Information System (INIS)

Li, Shou-lin; Ikeda, Jun; Takita, Tamotsu; Sekiguchi, Yohei; Demachi, Jun; Chikama, Hisao; Goto, Atsushi; Shirato, Kunio

1998-01-01

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine ( 123 I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of 123 I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of 123 I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). 123 I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of 123 I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the 123 I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

Energy Technology Data Exchange (ETDEWEB)

Kistrup, Kasper, E-mail: kkis@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Skotte Sørensen, Karen, E-mail: karen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Center for Integrated Point of Care Technologies (CiPoC), DELTA, Venlighedsvej 4, DK-2870 Hørsholm (Denmark); Wolff, Anders, E-mail: anders.wolff@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Fougt Hansen, Mikkel, E-mail: mikkel.hansen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark)

2015-04-15

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution.

An HPLC Method for Microanalysis and Pharmacokinetics of Marine Sulfated Polysaccharide PSS-Loaded Poly Lactic-co-Glycolic Acid (PLGA Nanoparticles in Rat Plasma

Directory of Open Access Journals (Sweden)

Hua-Shi Guan

2013-04-01

Full Text Available This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with d-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD at 250 nm (excitation and 435 nm (emission using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1–500 μg/mL, and the lower limit of detection (LLOD was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA nanoparticles (PSS-NP in rat plasma after a single intravenous (PSS only and oral administration (PSS and PSS-NP. Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability.

Crystallization of the Membrane-Associated Annexin B1: Roles of Additive Screen, Dynamic Light Scattering, and Bioactivity Assay

Energy Technology Data Exchange (ETDEWEB)

Ding, F.; Xu, Y; Azzi, A; Zhu, D; Rehse, D; Chen, C; Sun, S; Lin, S

2010-01-01

Annexin B1 (AnxB1) is a calcium-dependent phospholipid binding protein from Taenia solium cysticercus and has been reported to possess anticoagulant activity, to inhibit phospholipase A{sub 2}, and to regulate membrane transport. Native AnxB1 and its selenomethionyl derivative have been overproduced in Escherichia coli and purified. The results of dynamic light scattering analysis showed that Hepes buffer combined with low concentration salts (NaCl or CaCl{sub 2}) was beneficial for preventing aggregation and for AnxB1 stabilization in the storage. After the additive screen, crystals have been yielded in the presence of guanidine hydrochloride (Gn-HCl). We determined that a low concentration of Gn-HCl significantly delayed clotting time and increased anticoagulant activity. Analysis of the crystal showed that in the presence of Gn-HCl, AnxB1 crystallizes in orthorhombic space group, which is modified from the cubic space group for crystals grown in the absence of Gn-HCl. A high quality data set (at 1.9 {angstrom}) has been collected successfully for crystals of L-selenomethionine labeled protein in the presence of Gn-HCl, to solve the structure with the single anomalous dispersion method (SAD). The unit cell parameters are a = 102.35 {angstrom}, b = 103.59 {angstrom}, c = 114.60 {angstrom}, {alpha} = {beta} = {gamma} = 90.00{sup o}.

Promising silicones modified with cationic biocides for the development of antimicrobial medical devices.

Science.gov (United States)

Ghamrawi, Sarah; Bouchara, Jean-Philippe; Tarasyuk, Oksana; Rogalsky, Sergiy; Lyoshina, Lyudmila; Bulko, Olga; Bardeau, Jean-François

2017-06-01

We have tested silicones containing 2% or 5% of the cationic biocides polyhexamethylene guanidine dodecylbenzenesulfonate (PHMG-DBS), 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM-BF 4 ) or 1-dodecyl-3-methylimidazolium tetrafluoroborate (DMIM-BF 4 ) against the major relevant bacterial and yeast species in health care-associated infections (HCAI). Study conducted according to the international standard ISO 22196 revealed that silicones containing 2% or 5% DMIM-BF 4 or 5% PHMG-DBS presented the highest antimicrobial activity, leading to a logarithmic growth reduction of 3.03 to 6.46 and 3.65 to 4.85 depending on the bacterial or fungal species. Heat-pretreated silicones containing 2% DMIM-BF 4 kept a high activity, with at least a 3-log reduction in bacterial growth, except against P. aeruginosa where there was only a 1.1-log reduction. After 33days, the release ratio of cationic biocide from silicone films containing 5% of DMIM-BF 4 was found to be 5.6% in pure water and 1.9% in physiological saline solution, respectively. No leaching of PHMG-DBS polymeric biocide was detected under the same conditions. These results demonstrate unambiguously that silicones containing 2% DMIM-BF 4 or 5% PHMG-DBS present high antimicrobial activity, as well as high leaching resistance and therefore may be good candidates for the development of safer medical devices. Copyright © 2017 Elsevier B.V. All rights reserved.

Probing nanomechanical interaction at the interface between biological membrane and potentially toxic chemical.

Science.gov (United States)

Lim, Chanoong; Park, Sohee; Park, Jinwoo; Ko, Jina; Lee, Dong Woog; Hwang, Dong Soo

2018-04-12

Various xenobiotics interact with biological membranes, and precise evaluations of the molecular interactions between them are essential to foresee the toxicity and bioavailability of existing or newly synthesized molecules. In this study, surface forces apparatus (SFA) measurement and Langmuir trough based tensiometry are performed to reveal nanomechanical interaction mechanisms between potential toxicants and biological membranes for ex vivo toxicity evaluation. As a toxicant, polyhexamethylene guanidine (PHMG) was selected because PHMG containing humidifier disinfectant and Vodka caused lots of victims in both S. Korea and Russia, respectively, due to the lack of holistic toxicity evaluation of PHMG. Here, we measured strong attraction (Wad ∼4.2 mJ/m 2 ) between PHMG and head group of biological membranes while no detectable adhesion force between the head group and control molecules was measured. Moreover, significant changes in π-A isotherm of 1,2-Dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) monolayers were measured upon PHMG adsorption. These results indicate PHMG strongly binds to hydrophilic group of lipid membranes and alters the structural and phase behavior of them. More importantly, complementary utilization of SFA and Langmuir trough techniques are found to be useful to predict the potential toxicity of a chemical by evaluating the molecular interaction with biological membranes, the primary protective barrier for living organisms. Copyright © 2018 Elsevier B.V. All rights reserved.

5-(2-amimo-4-styryl pyrimidine-4-yl-4-methoxybenzofuran-6-ol

Directory of Open Access Journals (Sweden)

Atteyat A Labib

2013-05-01

Full Text Available This study describes the organic synthesis of 5-(2-amimo-4-styryl pyrimidine-4-yl-4-methoxy benzofuran-6-ol (SPBF as an example of a benzofuran derivative used as a new series of amyloid imaging agents. These benzofuran derivatives may be useful amyloid imaging agents for detecting B-amyloid plagues in the brain of Alzheimer’s disease. The precursor is 1-[6-hydroxy-4-methoxybenzofuran-5-yl]-phenyl butadiene ketone, which react with guanidine hydrochloride. The purification process was done via crystallization using solvent ethanol. The overall yield was 75% and the structure of the synthesized compound was confirmed by correct analytical and spectral data. Also, The synthesized compound was labeled with radioactive iodine -125 via electrophilic substitution reaction, in the presence of iodogen as an oxidizing agent, the labeling process was carried out at 95oC for 20min. The radiochemical yield was determined by using a thin layer chromatography and the yield was equal to 80%. Preliminary an in-vivo study examined normal mice after intravenous injection through the tail vein and the data showed the labeling compound was quickly cleared from most body organs. The radioiodinated compound showed high brain uptake.The results of this study suggest that radioiodinated (SPBF may be useful as a brain imaging agents.

Directory of Open Access Journals (Sweden)

Kamal M. El-Gamal

2016-12-01

Full Text Available A series of 3-substituted 6-methoxy-1H-pyrazolo [3,4-b]quinoline derivatives was synthesized by treating 6-methoxy-1H-pyrazolo[3,4-b]quinolin-3-amine (6 with different acid anhydrides including succinic anhydride, maleic anhydride and phthalic anhydride. Also, a series of 3-heteroaryl-2-chloro-6-methoxyquinolines was prepared through 1,3-dipolar cycloaddition of different bi-nucleophiles including hydrazine hydrate, hydroxylamine hydrochloride, thiourea, guanidine hydrochloride, urea and metformin hydrochloride to the chalcone derivative 3-(2-chloro-6-methoxyquinolin-3-yl-1-(4-methoxyphenylprop-2-en-1-one. Structural identifications of all products were reported and the new compounds were screened for their in vitro antimicrobial activity against Streptococcus pneumonia and Bacillus subtilis as examples for Gram-positive bacteria, Pseudomonas aeruginosa and Escherichia coli as examples for Gram-negative bacteria, and Aspergillus fumigatus, Syncephalastrum racemosum, Geotriucum candidum and Candida albicans as representative examples of fungi. The majority of tested compounds showed moderate activities against a wide range of the selected organisms. Among the tested compounds, pyrimidine derivatives 16 and 17 showed the highest antimicrobial activity against gram-positive strains while the highest activity against E. coli as example for Gram-negative strains was observed in the case of 11 and 17. Compounds 14 and 17 were found to be extremely potent against three of the selected fungal strains.

Improved Yield of High Molecular Weight DNA Coincides with Increased Microbial Diversity Access from Iron Oxide Cemented Sub-Surface Clay Environments

Science.gov (United States)

Hurt, Richard A.; Robeson, Michael S.; Shakya, Migun; Moberly, James G.; Vishnivetskaya, Tatiana A.; Gu, Baohua; Elias, Dwayne A.

2014-01-01

Despite over three decades of progress, extraction of high molecular weight (HMW) DNA from high clay soils or iron oxide cemented clay has remained challenging. HMW DNA is desirable for next generation sequencing as it yields the most comprehensive coverage. Several DNA extraction procedures were compared from samples that exhibit strong nucleic acid adsorption. pH manipulation or use of alternative ion solutions offered no improvement in nucleic acid recovery. Lysis by liquid N2 grinding in concentrated guanidine followed by concentrated sodium phosphate extraction supported HMW DNA recovery from clays high in iron oxides. DNA recovered using 1 M sodium phosphate buffer (PB) as a competitive desorptive wash was 15.22±2.33 µg DNA/g clay, with most DNA consisting of >20 Kb fragments, compared to 2.46±0.25 µg DNA/g clay with the Powerlyzer system (MoBio). Increasing PB concentration in the lysis reagent coincided with increasing DNA fragment length during initial extraction. Rarefaction plots of 16S rRNA (V1–V3 region) pyrosequencing from A-horizon and clay soils showed an ∼80% and ∼400% larger accessed diversity compared to the Powerlyzer soil DNA system, respectively. The observed diversity from the Firmicutes showed the strongest increase with >3-fold more operational taxonomic units (OTU) recovered. PMID:25033199

Highly Efficient One-Pot Synthesis of COS-Based Block Copolymers by Using Organic Lewis Pairs.

Science.gov (United States)

Yang, Jia-Liang; Cao, Xiao-Han; Zhang, Cheng-Jian; Wu, Hai-Lin; Zhang, Xing-Hong

2018-01-31

A one-pot synthesis of block copolymer with regioregular poly(monothiocarbonate) block is described via metal-free catalysis. Lewis bases such as guanidine, quaternary onium salts, and Lewis acid triethyl borane (TEB) were equivalently combined and used as the catalysts. By using polyethylene glycol (PEG) as the macromolecular chain transfer agent (CTA), narrow polydispersity block copolymers were obtained from the copolymerization of carbonyl sulfide (COS) and propylene oxide (PO). The block copolymers had a poly(monothiocarbonate) block with perfect alternating degree and regioregularity. Unexpectedly, the addition of CTA to COS/PO copolymerization system could dramatically improve the turnover frequency (TOF) of PO (up to 240 h -1 ), higher than that of the copolymerization without CTA. In addition, the conversion of CTA could be up to 100% in most cases, as revealed by ¹H NMR spectra. Of consequence, the number-average molecular weights ( M n s) of the resultant block copolymers could be regulated by varying the feed ratio of CTA to PO. Oxygen-sulfur exchange reaction (O/S ER), which can generate randomly distributed thiocarbonate and carbonate units, was effectively suppressed in all of the cases in the presence of CTA, even at 80 °C. This work presents a versatile method for synthesizing sulfur-containing block copolymers through a metal-free route, providing an array of new block copolymers.

Novel photoluminescence enzyme immunoassay based on supramolecular host-guest recognition using L-arginine/6-aza-2-thiothymine-stabilized gold nanocluster.

Science.gov (United States)

Wang, Youmei; Lu, Minghua; Tang, Dianping

2018-06-30

A new photoluminescence (PL) enzyme immunoassay was designed for sensitive detection of aflatoxin B 1 (AFB 1 ) via an innovative enzyme substrate, 6-aza-2-thiothymine-stabilized gold nanocluster (AAT-AuNC) with L-arginine. The enzyme substrate with strong PL intensity was formed through supramolecular host-guest assembly between guanidine group of L-arginine and AAT capped on the surface of AuNC. Upon arginase introduction, the captured L-arginine was hydrolyzed into ornithine and urea, thus resulting in the decreasing PL intensity. Based on this principle, a novel competitive-type immunoreaction was first carried out on AFB 1 -bovine serum albumin (AFB 1 -BSA) conjugate-coated microplate, using arginase-labeled anti-AFB 1 antibody as the competitor. Under the optimum conditions, the PL intensity increased with the increment of target AFB 1 , and allowed the detection of the analyte at concentrations as low as 3.2 pg mL -1 (ppt). Moreover, L-arginine-AAT-AuNC-based PL enzyme immunoassay afforded good reproducibility and acceptable specificity. In addition, the accuracy of this methodology, referring to commercial AFB 1 ELISA kit, was evaluated to analyze naturally contaminated or spiked peanut samples, giving well-matched results between two methods, thus representing a useful scheme for practical application in quantitative monitoring of mycotoxins in foodstuff. Copyright © 2018 Elsevier B.V. All rights reserved.

Biochemical properties of L-arabinose isomerase from Clostridium hylemonae to produce D-tagatose as a functional sweetener.

Science.gov (United States)

Nguyen, Tien-Kieu; Hong, Moon-Gi; Chang, Pahn-Shick; Lee, Byung-Hoo; Yoo, Sang-Ho

2018-01-01

d-Tagatose has gained substantial interest due to its potential functionalities as a sucrose substitute. In this study, the gene araA, encoding l-arabinose isomerase (l-AI) from Clostridium hylemonae (DSM 15053), was cloned and expressed in Escherichia coli BL21 (DE3). This gene consists of 1,506 nucleotides and encodes a protein of 501 amino acid residues with a calculated molecular mass of 56,554 Da. Since l-AI was expressed as an intracellular inclusion body, this enzyme was solubilized with guanidine hydrochloride, refolded, and activated with a descending concentration gradient of urea. The purified enzyme exhibited the greatest activity at 50°C, pH 7-7.5, and required 1 mM of Mg2+ as a cofactor. Notably, the catalytic efficiency (3.69 mM-1sec-1) of l-AI from C. hylemonae on galactose was significantly greater than that of other previously reported enzymes. The bioconversion yield of d-tagatose using the C. hylemonae l-arabinose isomerase at 60°C reached approximately 46% from 10 mM of d-galactose after 2 h. From these results, it is suggested that the l-arabinose isomerase from C. hylemonae could be utilized as a potential enzyme for d-tagatose production due to its high conversion yield at an industrially competitive temperature.

Conformational fluctuation dynamics of domain I of human serum albumin in the course of chemically and thermally induced unfolding using fluorescence correlation spectroscopy.

Science.gov (United States)

Yadav, Rajeev; Sengupta, Bhaswati; Sen, Pratik

2014-05-22

The present study elucidates the involvement of conformational fluctuation dynamics during chemically and thermally induced unfolding of human serum albumin (HSA) by fluorescence correlation spectroscopic (FCS) study, time-resolved fluorescence measurements, and circular dichroism (CD) spectroscopic methods. Two fluorescent probes, tetramethylrhodamine-5-maleimide (TMR) and N-(7-dimethylamino-4-methylcoumarin-3-yl) iodoacetamide (DACIA) were used to selectively label the domain I of HSA through the reaction with cys-34 for these studies. The guanidine hydrochloride (GnHCl) induced global structural change of HSA is monitored through its hydrodynamic radius (r(H)) and CD response, which is found to be two step in nature. In FCS experiment, along with the diffusion time component we have observed an exponential relaxation time component (τ(R)) that has been ascribed to the concerted chain dynamics of HSA. Unlike in the global structural change, we found that the τ(R) value changes in a different manner in the course of the unfolding. The dependence of τ(R) on the concentration of GnHCl was best fitted with a four state model, indicating the involvement of two intermediate states during the unfolding process, which were not observed through the CD response and r(H) data. The fluorescence lifetime measurement also supports our observation of intermediate states during the unfolding of HSA. However, no such intermediate states were observed during thermally induced unfolding of HSA.

SKF 525-A and cytochrome P-450 ligands inhibit with high affinity the binding of [3H]dextromethorphan and σligands to guinea pig brain

International Nuclear Information System (INIS)

Klein, M.; Canoll, P.D.; Musacchio, J.M.

1991-01-01

The DM 1 /σ 1 site binds dextromethorphan (DM) and σ receptor ligands. The broad binding specificity of this site and its peculiar subcellular distribution prompted us to explore the possibility that this site is a member of the cytochrome P-450 superfamily of enzymes. We tested the effects of the liver microsomal monooxygenase inhibitor SKF 525-A (Proadifen), and other P-450 substrates on the binding of [ 3 H]dextromethorphan, [ 3 H]3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine and (+)-[ 3 H]1,3-Di-o-tolyl-guanidine ([ 3 H]DTG) to the guinea pig brain. SKF 525-A, l-lobeline and GBR-12909 inhibited the binding of the three labeled ligands with nM affinity. Each drug has identical nM K i values for the high-affinity site labeled by the three ligands. This indicated that they displaced the labeled ligands from the common DM 1 σ 1 site. Debrisoquine and sparteine, prototypical substrates for liver debrisoquine 4-hydroxylase, displayed K i values of 9-13 and 3-4 μM respectively against the three labeled ligands. These results, the broad specificity of the DM 1 /σ 1 binding site, and its peculiar subcellular distribution, raises the possibility that this binding site is a member of the cytochrome P-450 superfamily of isozymes, rather than a neurotransmitter receptor

Empirical Correction for Differences in Chemical Exchange Rates in Hydrogen Exchange-Mass Spectrometry Measurements.

Science.gov (United States)

Toth, Ronald T; Mills, Brittney J; Joshi, Sangeeta B; Esfandiary, Reza; Bishop, Steven M; Middaugh, C Russell; Volkin, David B; Weis, David D

2017-09-05

A barrier to the use of hydrogen exchange-mass spectrometry (HX-MS) in many contexts, especially analytical characterization of various protein therapeutic candidates, is that differences in temperature, pH, ionic strength, buffering agent, or other additives can alter chemical exchange rates, making HX data gathered under differing solution conditions difficult to compare. Here, we present data demonstrating that HX chemical exchange rates can be substantially altered not only by the well-established variables of temperature and pH but also by additives including arginine, guanidine, methionine, and thiocyanate. To compensate for these additive effects, we have developed an empirical method to correct the hydrogen-exchange data for these differences. First, differences in chemical exchange rates are measured by use of an unstructured reporter peptide, YPI. An empirical chemical exchange correction factor, determined by use of the HX data from the reporter peptide, is then applied to the HX measurements obtained from a protein of interest under different solution conditions. We demonstrate that the correction is experimentally sound through simulation and in a proof-of-concept experiment using unstructured peptides under slow-exchange conditions (pD 4.5 at ambient temperature). To illustrate its utility, we applied the correction to HX-MS excipient screening data collected for a pharmaceutically relevant IgG4 mAb being characterized to determine the effects of different formulations on backbone dynamics.

Purification of inclusion bodies using PEG precipitation under denaturing conditions to produce recombinant therapeutic proteins from Escherichia coli.

Science.gov (United States)

Chen, Huanhuan; Li, Ninghuan; Xie, Yueqing; Jiang, Hua; Yang, Xiaoyi; Cagliero, Cedric; Shi, Siwei; Zhu, Chencen; Luo, Han; Chen, Junsheng; Zhang, Lei; Zhao, Menglin; Feng, Lei; Lu, Huili; Zhu, Jianwei

2017-07-01

It has been documented that the purification of inclusion bodies from Escherichia coli by size exclusion chromatography (SEC) may benefit subsequent refolding and recovery of recombinant proteins. However, loading volume and the high cost of the column limits its application in large-scale manufacturing of biopharmaceutical proteins. We report a novel process using polyethylene glycol (PEG) precipitation under denaturing conditions to replace SEC for rapid purification of inclusion bodies containing recombinant therapeutic proteins. Using recombinant human interleukin 15 (rhIL-15) as an example, inclusion bodies of rhIL-15 were solubilized in 7 M guanidine hydrochloride, and rhIL-15 was precipitated by the addition of PEG 6000. A final concentration of 5% (w/v) PEG 6000 was found to be optimal to precipitate target proteins and enhance recovery and purity. Compared to the previously reported S-200 size exclusion purification method, PEG precipitation was easier to scale up and achieved the same protein yields and quality of the product. PEG precipitation also reduced manufacturing time by about 50 and 95% of material costs. After refolding and further purification, the rhIL-15 product was highly pure and demonstrated a comparable bioactivity with a rhIL-15 reference standard. Our studies demonstrated that PEG precipitation of inclusion bodies under denaturing conditions holds significant potential as a manufacturing process for biopharmaceuticals from E. coli protein expression systems.

Amphotericin B induced interdigitation of apolipoprotein stabilized nanodisk bilayers

Energy Technology Data Exchange (ETDEWEB)

Nguyen, T; Weers, P M; Sulchek, T; Hoeprich, P D; Ryan, R O

2006-12-07

Amphotericin B nanodisks (AMB-ND) are ternary complexes of AMB, phospholipid (PL) and apolipoprotein organized as discrete nanometer scale disk-shaped bilayers. In gel filtration chromatography experiments, empty ND lacking AMB elute as a single population of particles with a molecular weight in the range of 200 kDa. AMB-ND formulated at a 4:1 PL:AMB weight ratio, separated into two peaks. Peak 1 eluted at the position of control ND lacking AMB while the second peak, containing all of the AMB present in the original sample, eluted in the void volume. When ND prepared with increased AMB (1:1 phospholipid:AMB molar ratio) were subjected to gel filtration chromatography, an increased proportion of phospholipid and apolipoprotein were recovered in the void volume with the AMB. Prior to gel filtration the AMB-ND sample could be passed through a 0.22 {micro}m filter without loss of AMB while the voided material was lost. Native gel electrophoresis studies corroborated the gel permeation chromatography data. Far UV circular dichroism analyses revealed that apoA-I associated with AMB-ND denatures at a lower guanidine HCl concentration than apoA-I associated with ND lacking AMB. Atomic force microscopy revealed that AMB induces compression of the ND bilayer thickness consistent with bilayer interdigitation, a phenomenon that is likely related to the ability of AMB to induce pore formation in susceptible membranes.

Guanidinylated 3-gluconamidopropyl methacrylamide-s-3-aminopropyl methacrylamide copolymer as siRNA carriers for inhibiting human telomerase reverse transcriptase expression.

Science.gov (United States)

Wu, Yang; Ji, Jinkai; Yang, Ran; Zhang, Xiaoqiang; Li, Yuanhui; Pu, Yuepu; Li, Xinsong

2013-01-01

In this report, a series of well-defined glucose- and guanidine-based cationic copolymers as gene carriers were developed to inhibit human telomerase reverse transcriptase (hTERT) gene expression. First of all, guandinylated 3-gluconamidopropyl methacrylamide-s-3-aminopropyl methacrylamide copolymers (guanidinylated GAPMA-s-APMA, abbreviated as GGA) were prepared via aqueous reversible addition--fragmentation chain transfer polymerization (RAFT). Then, three target hTERT siRNA TERT-1, TERT-2 and TERT-3 were designed and combined with GGA copolymers to form siRNA/GGA polyplexes. The polyplexes were examined by dynamic light scattering and agarose gel electrophoresis. The results indicated that GGA copolymers can condense siRNA effectively to form particles with the diameter from 157 nm to 411 nm and zeta potential values in the range from +3.7 to +15.8 mV at various charge ratios (N/P). The MTT assay data of siRNA/GGA polyplexes on human hepatocellular liver carcinoma cells (HepG2) indicated that GGA copolymer had better cell viabilities than polyethylenimine (PEI). Furthermore, the transfection of siRNA/GGA polyplexes was detected by real-time quantitative PCR (RT-qPCR) in HepG2. It was found that siRNA/GGA polyplexes could effectively silence hTERT mRNA expression in serum-free media (paminopropyl methacrylamide copolymers might be promise in gene delivery.

Mussel glue protein has an open conformation.

Science.gov (United States)

Williams, T; Marumo, K; Waite, J H; Henkens, R W

1989-03-01

Both native glue protein from marine mussels and a synthetic nonhydroxylated analog were analyzed by far-uv CD under a variety of conditions. Analysis of the CD spectra using various models strongly suggest a primarily random coil structure for both forms of the protein, a fact also supported by the absence of spectral change for the glue protein upon dilution into 6 M guanidine hydrochloride. The nonhydroxylated analog, which consists of 20 repeats of the peptide sequence Ala-Lys-Pro-Ser-Tyr-Pro-Pro-Thr-Tyr-Lys, was further characterized by enzyme modification using mushroom tyrosinase. Enzymatic hydroxylation of tyrosines was found to be best fit by a model containing two rate constants, 5.6 (+/- 0.6) X 10(-3) and 7.2 (+/- 0.3) X 10(-2) min-1. At equilibrium, HPLC analysis of digests showed nearly 100% conversion of Tyr-9 and only 15 to 35% conversion of Tyr-5. The Chou and Fasman rules for predicting structure were applied to the repeat sequence listed above. The rules predict the absence of alpha helix and beta pleated sheets in the structure of this peptide. On the other hand, beta turns are predicted to be present with Tyr-5 being in the region of highest probability. These data suggest that the protein in solution has only a small amount of secondary structure.

Enhancing the intestinal absorption of molecules containing the polar guanidino functionality: a double-targeted prodrug approach.

Science.gov (United States)

Sun, Jing; Dahan, Arik; Amidon, Gordon L

2010-01-28

A prodrug strategy was applied to guanidino-containing analogues to increase oral absorption via hPEPT1 and hVACVase. l-Valine, l-isoleucine, and l-phenylalanine esters of [3-(hydroxymethyl)phenyl]guanidine (3-HPG) were synthesized and evaluated for transport and activation. In HeLa/hPEPT1 cells, Val-3-HPG and Ile-3-HPG exhibited high affinity to hPEPT1 (IC(50): 0.65 and 0.63 mM, respectively), and all three l-amino acid esters showed higher uptake (2.6- to 9-fold) than the parent compound 3-HPG. Val-3-HPG and Ile-3-HPG demonstrated remarkable Caco-2 permeability enhancement, and Val-3-HPG exhibited comparable permeability to valacyclovir. In rat perfusion studies, Val-3-HPG and Ile-3-HPG permeabilities were significantly higher than 3-HPG and exceeded/matched the high-permeability standard metoprolol, respectively. All the l-amino acid 3-HPG esters were effectively activated in HeLa and Caco-2 cell homogenates and were found to be good substrates of hVACVase (k(cat)/K(m) in mM(-1) x s(-1): Val-3-HPG, 3370; Ile-3-HPG, 1580; Phe-3-HPG, 1660). In conclusion, a prodrug strategy is effective at increasing the intestinal permeability of polar guanidino analogues via targeting hPEPT1 for transport and hVACVase for activation.

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

International Nuclear Information System (INIS)

Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

2015-01-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution

Modulation of gene expression in small follicle porcine granulosa cells by human follicle stimulating hormone (hFSH)

Energy Technology Data Exchange (ETDEWEB)

Calvo, F.O.; Ryan, R.J.; Woloschak, G.E.

1986-03-01

Small follicle (1-3 mm) porcine granulosa cells (SFPGF) were isolated by puncture, aspiration and cultured under standard conditions in DMEM, HEPES, BSA, MIX. At the start of culture, cells were stimulated with 100ng hFSH/ml. At various times afterwards total cellular RNA was prepared using guanidine-hydrochloride solubilization, phenol extraction and precipitation from 3M NaOAc, pH 6.0. RNA was 5'-end labelled with /sup 32/P in a kinase reaction and hybridized to an excess of clone-specific DNA immobilized on nitrocellulose filters using stringent hybridization and wash conditions. After autoradiography the RNA hybridized to the DNA blot filter were quantitated by microdensitometry. Hybridization to parent plasmid was negative. RNA derived from control cultures showed patterns of hybridization similar to those obtained from freshly obtained cells. Results of these experiments demonstrate hFSh induction of RNA specific for transferrin receptor, ..cap alpha..-interferon, H-ras, and K-ras. Increased RNA levels were apparent within 10 min of treatment and had declined by 180 min. Expression of actin, p53 and for RNAs declined by 10 min of hFSH addition but was enhanced by 160 min. Levels of ..beta..-interferon, myc, mos, abl and yb RNAs were not detectable under these conditions. These results demonstrate specific gene modulation in SFPGC cultured with hFSH.

Histones H10a and H10b are the same as CHO histones H1(III) and H1(IV):new features of H10 phosphorylation during the cell cycle

International Nuclear Information System (INIS)

D'Anna, J.A.; Gurley, L.R.; Becker, R.R.

1981-01-01

Two histone H1 fractions [H1(I) and H1(II) and two histone H1 0 fractions (H1 0 a and H1 0 b) have been isolated from butyrate-treated Chinese hamster (line CHO) cells by guanidine hydrochloride gradient chromatography on Bio-Rex 70 ion-exchange resin. The fractions have been identified by electrophoresis and amino acid analyses. Electrophoretic analysis of cyanogen bromide treated H1 0 in long acid-urea-polyacrylamide gels suggests that H1 0 a and H1 0 b differ, at least, within the 20-30 residue fragment(s) removed by the cyanogen bromide clevage. Shallow-gradient Bio-Rex 70 chromatography indicates that histones H1 0 a and H1 0 b are the same as the respective CHO histones, H1(III) and H1(IV). This identification and the phosphate incorporation data of Gurley et al. (1975) reveal new features about H1 0 phosphorylation: (1) following release from G 1 arrest, H1 0 a and H1 0 b become phosphorylated in late G 1 prior to DNA synthesis; (2) H1 0 a and H1 0 b are phosphorylated at similar rates throughout the cell cycle. These and other data demonstrate that histone H1 0 is phosphorylated in a cell cycle dependent fashion which mimics that of histone H1

Multi-podant diglycolamides and room temperature ionic liquid impregnated resins: An excellent combination for extraction chromatography of actinides.

Science.gov (United States)

Gujar, R B; Ansari, S A; Verboom, W; Mohapatra, P K

2016-05-27

Extraction chromatography resins, prepared by impregnating two multi-podant diglycolamide ligands, viz. diglycolamide-functionalized calix[4]arene (C4DGA) and tripodal diglycolamide (T-DGA) dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (RTIL: C4mimTf2N) on Chromosorb-W (an inert solid support), gave excellent results for the removal of trivalent actinides from acidic waste solutions. Distribution coefficient measurements on several metal ions showed selective sorption of Am(III) over hexavalent uranyl ions and other fission product elements such as strontium and cesium. The sorbed metal ions could be efficiently desorbed with a complexing solution containing guanidine carbonate and EDTA buffer. The sorption of Am(III) on both resins followed pseudo-second order rate kinetics with rate constants of 1.37×10(-6) and 6.88×10(-7)g/cpmmin for T-DGA and C4DGA resins, respectively. The metal sorption on both resins indicated the Langmuir monolayer chemisorption phenomenon with Eu(III) sorption capacities of 4.83±0.21 and 0.52±0.05mg per g of T-DGA and C4DGA resins, respectively. The results of column studies show that these resins are of interest for a possible application for the recovery of hazardous trivalent actinides from dilute aqueous solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

Enzyme stability, thermodynamics and secondary structures of α-amylase as probed by the CD spectroscopy.

Science.gov (United States)

Kikani, B A; Singh, S P

2015-11-01

An amylase of a thermophilic bacterium, Bacillus sp. TSSC-3 (GenBank Number, EU710557) isolated from the Tulsi Shyam hot spring reservoir (Gujarat, India) was purified to the homogeneity in a single step on phenyl sepharose 6FF. The molecular weight of the enzyme was 25kD, while the temperature and pH optima for the enzyme catalysis were 80°C and 7, respectively. The purified enzyme was highly thermostable with broad pH stability and displayed remarkable resistance against surfactants, chelators, urea, guanidine HCl and various solvents as well. The stability and changes in the secondary structure of the enzyme under various extreme conditions were determined by the circular dichroism (CD) spectroscopy. The stability trends and the changes in the α-helices and β-sheets were analyzed by Mean Residual Ellipticity (MRE) and K2D3. The CD data confirmed the structural stability of the enzyme under various harsh conditions, yet it indicated reduced α-helix content and increased β-sheets upon denaturation. The thermodynamic parameters; deactivation rate constant, half-life, changes in entropy, enthalpy, activation energy and Gibb's free energy indicated that the enzyme-substrate reactions were highly stable. The overall profile of the enzyme: high thermostability, alkalitolerance, calcium independent nature, dextrose equivalent values and resistance against chemical denaturants, solvents and surfactants suggest its commercial applications. Copyright © 2015 Elsevier B.V. All rights reserved.

The mixed-valent copper thiolate complex hexakis{μ3-2-[(1,3-dimethylimidazolideneamino]benzenethiolato}dicopper(IItetracopper(I bis(hexafluoridophosphate acetonitrile disolvate dichloromethane disolvate

Directory of Open Access Journals (Sweden)

Adam Neuba

2013-01-01

Full Text Available The molecular structure of the title compound, [Cu4ICu2II(C11H14N3S6](PF62·2CH3CN·2CH2Cl2, shows a mixed-valent copper(I/II thiolate complex with a distorted tetrahedral coordination of the CuI and CuII cations by one guanidine N atom and three S atoms each. Characteristic features of the Cu6S6 skeleton are a total of six chemically identical μ3-thiolate bridges and almost planar Cu2S2 units with a maximum deviation of 0.110 (1 Å from the best plane. Each Cu2S2 unit then shares common Cu–S edges with a neighbouring unit; the enclosed dihedral angle is 60.14 (2°. The geometric centre of the Cu6S6 cation lies on a crystallographic inversion centre. Cu—S bond lengths range from 2.294 (1 to 2.457 (1 Å, Cu—N bond lengths from 2.005 (3 to 2.018 (3 Å and the non-bonding Cu...Cu distances from 2.5743 (7 to 2.5892 (6 Å. C—H...F hydrogen-bond interactions occur between the PF6− anion and the complex molecule and between the PF6− anion and the acetonitrile solvent molecule.

Alkylation of amide linkages and cleavage of the C chain in the enzyme-activated-substrate inhibition of alpha-chymotrypsin with N-nitrosamides

International Nuclear Information System (INIS)

Donadio, S.; Perks, H.M.; Tsuchiya, K.; White, E.H.

1985-01-01

Active-site-directed N-nitrosamides inhibit alpha-chymotrypsin through an enzyme-activated-substrate mechanism. In this work, the activation results in the release--in the active site--of benzyl carbonium ions, which alkylate and inhibit the enzyme. The final ratio of benzyl groups to enzyme molecules is 1.0, but the alkyl groups are scattered over a number of sites. Reduction and alkylation of the inhibited enzyme generate peptides insoluble in most media. Guanidine hydrochloride at 6 M proved a good solvent, and its use as an eluant on G-75 Sephadex permitted separation of the peptides. In the case of 14 C-labeled enzyme, such an approach has shown that all of the alkylation occurs on the C chain of the enzyme, the chain of which the active site is constructed. Chemical modification of the peptides with ethylenediamine and N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide rendered them soluble in dilute acid, permitting high-performance liquid chromatographic separation. Model studies have shown that the benzyl carbonium ions are highly reactive, alkylating amide linkages at both oxygen and nitrogen. Chromatography of this mixture and also 13 C NMR spectroscopy of the intact inhibited enzyme have shown that three major N-alkylations have occurred. Tryptic digestion of the C chain of chymotrypsin, which contains all of the alkylation sites, provides evidence that the stable N sites are principally located between residue 216 and residue 230

Rate of humidifier and humidifier disinfectant usage in Korean children: A nationwide epidemiologic study.

Science.gov (United States)

Yoon, Jisun; Cho, Hyun-Ju; Lee, Eun; Choi, Yean Jung; Kim, Young-Ho; Lee, Jung Lym; Lee, Ye Jin; Hong, Soo-Jong

2017-05-01

In South Korea, a cluster of humidifier disinfectant-induced lung injury (HDLI) cases developed between 2006 and 2011. There are no existing reports regarding the rate of humidifier disinfectant (HD) usage in the general population of Korean children. The purpose of this study was to investigate the rate of humidifier and HD usage in the general population of Korean children. This is a general population-based birth cohort multicenter study, Panel Study of Korean Children (PSKC) from 2008, a humidifier and HD-related questionnaire administered to 1577 subjects (809 male, 768 female) in 2015 (n=1577). The questionnaire consisted of four categories (humidifier usage, HD usage, exposure duration, and type of HD brands). A total of 75.6% (1192/1577) had used a humidifier, and the rate of HD usage was found to be 31.1% (409/1316). Polyhexamethylene guanidine (PHMG), used as a disinfectant, was found to have the highest usage rate (62.0%). HD was used for less than 3 months of the entire lifetime of most of the subjects. In conclusion, approximately 30% of young Korean children were exposed to HD. PHMG-containing HD was the most commonly used. These results suggest that a nationwide epidemiologic investigation is needed urgently, and children exposed to HD should be investigated regarding their status of lung injury, including a pulmonary function test. Moreover, a long-term follow-up period may be required to evaluate HD usage-associated lung injury. Copyright © 2017 Elsevier Inc. All rights reserved.

Autoclaving-Derived Surface Coating with In Vitro and In Vivo Antimicrobial and Antibiofilm Efficacies.

Science.gov (United States)

Su, Yajuan; Zhi, Zelun; Gao, Qiang; Xie, Meihua; Yu, Meng; Lei, Bo; Li, Peng; Ma, Peter X

2017-03-01

Biomedical device-associated infections which engender severe threat to public health require feasible solutions. In this study, block copolymers consisting of antimicrobial, antifouling, and surface-tethering segments in one molecule are synthesized and grafted on polymeric substrates by a facile plasma/autoclave-assisted method. Hetero-bifunctional polyethylene glycol (PEG) with allyl and tosyl groups (APEG-OTs) is first prepared. PEGs with different molecular weights (1200 and 2400 Da) are employed. Polyhexamethylene guanidine (PHMG) which has excellent broad-spectrum antimicrobial activity and thermal/chemical stability, is conjugated with APEG-OTs to generate the block copolymer (APEG-PHMG). Allyl terminated PHMG (A-PHMG) without PEG segments is also synthesized by reacting PHMG with allyl glycidyl ether. The synthesized copolymers are thermal initiated by autoclaving and grafted on plasma pretreated silicone surface, forming permanently bonded bottlebrush-like coatings. Both A-PHMG and APEG 1200/2400 -PHMG coatings exhibit potent antimicrobial activity against gram-positive/negative bacteria and fungus, whereas APEG 1200/2400 -PHMG coatings show superior antifouling activity and long-term reusability to A-PHMG coating. APEG 2400 -PHMG coating demonstrates the most effective in vitro antibiofilm and protein/platelet-resistant properties, as well as excellent hemo/biocompatibility. Furthermore, APEG 2400 -PHMG greatly reduces the bacteria number with 5-log reduction in a rodent subcutaneous infection model. This rationally designed dual-functional antimicrobial and antifouling coating has great potential in combating biomedical devices/implant-associated infections. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two Cases of Chloromethylisothiazolinone and Methylisothiazolinone-associated Toxic Lung Injury.

Science.gov (United States)

Lee, Eun; Son, Seung Kook; Yoon, Jisun; Cho, Hyun Ju; Yang, Song I; Jung, Sungsu; Do, Kyung Hyun; Cho, Young Ah; Lee, So Yeon; Park, Dong Uk; Hong, Soo Jong

2018-04-16

Previous animal studies have not conclusively determined the association between exposure to humidifier disinfectants (HDs) containing 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and/or 2-methyl-4-isothiazolin-3-one (MIT) and development of HD-associated lung injuries. Nonetheless, patients exposed to HDs containing only CMIT and/or MIT showed clinically similar lung injuries to those exposed to HDs containing polyhexamethylene guanidine (PHMG) or oligo (2-[2-ethoxy]ethoxyethyl) guanidinium chloride (PGH). Here, we report twin sisters with lung injuries associated with exposure to CMIT/MIT-containing HDs. At 6 months of age, a younger twin sister presented with the 3-day history of cough, sputum, and respiratory difficulty. Chest radiography revealed multiple patchy consolidation and ground-glass opacities with pneumothorax and pneumomediastinum. Thoracostomy was performed due to pneumothorax at admission and she was discharged at 11 days of hospitalization. At 5 years of age, multiple tiny nodules and faint centrilobular ground-glass opacities were observed with the small pneumatocele. The elder sister visited a tertiary hospital due to dyspnea at 12 months of age. Chest radiography showed consolidation, pneumomediastinum, and pulmonary interstitial emphysema. There was no response to the administration of immunosuppressant drugs and antifibrotic agents. At 5 years of age, chest CT revealed ground-glass opacity and multiple tiny centrilobular ground-glass opacities nodules in both lungs with exercise intolerance. © 2018 The Korean Academy of Medical Sciences.

A tetrodotoxin-binding protein in the hemolymph of shore crab Hemigrapsus sanguineus: purification and properties.

Science.gov (United States)

Nagashima, Yuji; Yamamoto, Kazuhiko; Shimakura, Kuniyoshi; Shiomi, Kazuo

2002-06-01

The shore crab Hemigrapsus sanguineus hemolymph contains soluble proteins that bind tetrodotoxin (TTX) and are responsible for high resistance of the crab to TTX. The TTX-binding protein was purified from the hemolymph by ultrafiltration, lectin affinity chromatography and gel filtration HPLC. The purified protein gave only one band in native-polyacrylamide gel electrophoresis (PAGE), confirming its homogeneity. Its molecular weight was estimated to be about 400k by gel filtration HPLC, while it was estimated to be about 82k under non-reducing conditions and about 72 and 82k under reducing conditions by SDS-PAGE, indicating that the TTX-binding protein was composed of at least two distinct subunits. The TTX-binding protein was an acidic glycoprotein with pI 3.5, abundant in Asp and Glu but absent in Trp, and contained 6% reducing sugar and 12% amino sugar. The protein selectively bound to TTX, with a neutralizing ability of 6.7 mouse unit TTX/mg protein, but not to paralytic shellfish poisoning toxins. However, its neutralizing activity was almost lost by treatments with enzymes (protease XIV, thermolysin, trypsin, amyloglucosidase and alpha-amylase) and denaturing agents (1% SDS, 1% dithiothreitol, 8 M urea and 6 M guanidine hydrochloride), suggesting the involvement of both proteinaceous and sugar moieties in the binding to TTX and the importance of the steric conformation of the TTX-binding protein. Copright 2002 Elsevier Science Ltd.

Binding of a cementum attachment protein to extracellular matrix components and to dental surfaces

Energy Technology Data Exchange (ETDEWEB)

Pitaru, S; Hekmati, H [Department of Oral Biology, Goldschleger School of Dental Medicine, Tel Aviv University (Israel); Savion, N [Goldschleger Eye Institute, Sackler School of Medicine, Tel Aviv University (Israel); Olsen, S; Narayanan, S A [Department of Pathology, School of Medicine, University of Washington, Seattle, Washington (United States)

1992-01-01

Cementum proteins (CP) have been shown to mediate cell attachment. Among these, a 55 kDa protein was isolated. The purpose of the present study was to assess the capacity of CP to bind to non-demineralized and demineralized root surfaces and to support cell attachment to dentin. CP were prepared by sequential extraction of bovine cementum with 25 mM EDTA, 0.5 M acetic acid followed by 4 M guanidine HCl. The latter was subjected to ion exchange chromatography on a DEAE-3SW column and eluted stepwise with a 0-0.5 M NaCl gradient. CP were labelled with [sup 125]I and the capacity of [sup 125]I-CP to bind to mineralized and partially demineralized dentin, synthetic hydroxyapatite, collagen, fibronectin and fibrillar collagen-fibronectin cimplex was assessed. It was found that CP bind specifically to mineralized dentin and synthetic hydroxyapatite but not to demineralized dentin. The specific binding was 60% of the total binding. SDS-PAGE analysis of the proteins bound to dentin indicated that the main bound protein had a molecular weight of 55 kDa. CP exhibited high affinity for fibronectin (k[sub D] = 1.56 x 10[sup -10] M) and fibronectincollagen complex, but their binding to either molecular or fibrillar collagen was negligible. It is suggested that CP may play an important role in the attachment of cells of the periodontium to cementum extracellular matrix during homeostasis and regeneration. (au).

A Mutational Analysis of Residues in Cholera Toxin A1 Necessary for Interaction with Its Substrate, the Stimulatory G Protein Gsα

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Michael G. Jobling

2015-03-01

Full Text Available Pathogenesis of cholera diarrhea requires cholera toxin (CT-mediated adenosine diphosphate (ADP-ribosylation of stimulatory G protein (Gsα in enterocytes. CT is an AB5 toxin with an inactive CTA1 domain linked via CTA2 to a pentameric receptor-binding B subunit. Allosterically activated CTA1 fragment in complex with NAD+ and GTP-bound ADP-ribosylation factor 6 (ARF6-GTP differs conformationally from the CTA1 domain in holotoxin. A surface-exposed knob and a short α-helix (formed, respectively, by rearranging “active-site” and “activation” loops in inactive CTA1 and an ADP ribosylating turn-turn (ARTT motif, all located near the CTA1 catalytic site, were evaluated for possible roles in recognizing Gsα. CT variants with one, two or three alanine substitutions at surface-exposed residues within these CTA1 motifs were tested for assembly into holotoxin and ADP-ribosylating activity against Gsα and diethylamino-(benzylidineamino-guanidine (DEABAG, a small substrate predicted to fit into the CTA1 active site. Variants with single alanine substitutions at H55, R67, L71, S78, or D109 had nearly wild-type activity with DEABAG but significantly decreased activity with Gsα, suggesting that the corresponding residues in native CTA1 participate in recognizing Gsα. As several variants with multiple substitutions at these positions retained partial activity against Gsα, other residues in CTA1 likely also participate in recognizing Gsα.

Bromopyruvate, an active site-directed inactivator of E. coli 2-keto-4-hydroxyglutarate(KHG) aldolase, modifies glutamic acid residue-45

International Nuclear Information System (INIS)

Vlahos, C.J.; Dekker, E.E.

1987-01-01

E. coli KHG-aldolase (2-keto-4-hydroxyglutarate ↔ pyruvate + glyoxylate), a novel trimeric Class I aldolase, requires one active-site lysine residue (Lys 133)/subunit for Schiff-base formation as well as one arginine residue (Arg 49)/subunit for catalytic activity. The substrate analog, 3-bromopyruvate (BRPY), causes a time- and concentration-dependent loss of KHG-aldolase activity. This inactivation is regarded as active site-directed since: (a) BRPY modification results in complete loss of enzymatic activity; (b) saturation kinetics are exhibited, suggesting that a reversible complex is formed between the aldolase and BRPY prior to the rate-limiting inactivation step; (c) over 90% of the initial aldolase activity is protected by either substrate, pyruvate or KHG; (d) 1.1 mol of 14 C-BRPY is bound/enzyme subunit. Peptide isolation and sequencing show that the incorporated radioactivity is associated with residue Glu-45. Denaturation of the enzyme with guanidine x HCl following treatment with excess 14 C-BRPY allows for the incorporation of carbon-14 at Cys-159 and Cys-180 as well. The presence of pyruvate protects Glu-45 from being esterified but does not prevent the alkylation of the two cysteine residues. These results suggest that Glu-45 is essential for the catalytic activity of E. coli KHG-aldolase, most likely functioning as the active-site amphoteric proton donor/acceptor moiety that is involved in the overall mechanism of the reaction catalyzed by this enzyme

Molecular design of flotation collectors: A recent progress.

Science.gov (United States)

Liu, Guangyi; Yang, Xianglin; Zhong, Hong

2017-08-01

The nature of froth flotation is to selectively hydrophobize valuable minerals by collector adsorption so that the hydrophobized mineral particles can attach air bubbles. In recent years, the increasing commercial production of refractory complex ores has been urgent to develop special collectors for enhancing flotation separation efficiency of valuable minerals from these ores. Molecular design methods offer an effective way for understanding the structure-property relationship of flotation collectors and developing new ones. The conditional stability constant (CSC), molecular mechanics (MM), quantitative structure-activity relationship (QSAR), and first-principle theory, especially density functional theory (DFT), have been adopted to build the criteria for designing flotation collectors. Azole-thiones, guanidines, acyl thioureas and thionocarbamates, amide-hydroxamates, and double minerophilic-group surfactants such as Gemini, dithiourea and dithionocarbamate molecules have been recently developed as high-performance collectors. To design hydrophobic groups, the hydrophilic-hydrophobic balance parameters have been extensively used as criteria. The replacement of aryl group with aliphatic group or CC single bond(s) with CC double bond(s), reduction of carbon numbers, introduction of oxygen atom(s) and addition of trisiloxane to the tail terminal have been proved to be useful approaches for adjusting the surface activity of collectors. The role of molecular design of collectors in practical flotation applications was also summarized. Based on the critical review, some comments and prospects for further research on molecular design of flotation collectors were also presented in the paper. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved protein hydrogen/deuterium exchange mass spectrometry platform with fully automated data processing.

Science.gov (United States)

Zhang, Zhongqi; Zhang, Aming; Xiao, Gang

2012-06-05

Protein hydrogen/deuterium exchange (HDX) followed by protease digestion and mass spectrometric (MS) analysis is accepted as a standard method for studying protein conformation and conformational dynamics. In this article, an improved HDX MS platform with fully automated data processing is described. The platform significantly reduces systematic and random errors in the measurement by introducing two types of corrections in HDX data analysis. First, a mixture of short peptides with fast HDX rates is introduced as internal standards to adjust the variations in the extent of back exchange from run to run. Second, a designed unique peptide (PPPI) with slow intrinsic HDX rate is employed as another internal standard to reflect the possible differences in protein intrinsic HDX rates when protein conformations at different solution conditions are compared. HDX data processing is achieved with a comprehensive HDX model to simulate the deuterium labeling and back exchange process. The HDX model is implemented into the in-house developed software MassAnalyzer and enables fully unattended analysis of the entire protein HDX MS data set starting from ion detection and peptide identification to final processed HDX output, typically within 1 day. The final output of the automated data processing is a set (or the average) of the most possible protection factors for each backbone amide hydrogen. The utility of the HDX MS platform is demonstrated by exploring the conformational transition of a monoclonal antibody by increasing concentrations of guanidine.

Relative IGF-1 and IGF-2 gene expression in maternal and fetal tissues from diabetic swine

International Nuclear Information System (INIS)

Wolverton, C.K.; Leaman, D.W.; White, M.E.; Ramsay, T.G.

1990-01-01

Fourteen pregnant, crossbred gilts were utilized in this study. Seven gilts were injected with alloxan (50 mg/kg) at day 75 of gestation to induce diabetes. Gilts underwent caesarean section on day 105 of gestation. Samples were collected from maternal skeletal muscle, adipose tissue, uterus and endometrium; and from fetal skeletal muscle, adipose tissue, placenta, liver, lung, kidney, heart, brain and spleen. Tissues were frozen in liquid nitrogen for later analysis of IGF-1 and IGF-2 gene expression. Samples were pooled and total RNA was isolated using the guanidine isothiocynate method. Total mRNA was analyzed by dot blot hybridization. Blots were probed with 32 P-cDNA for porcine IGF-1 and rat IGF-2. IGF-1 gene expression in maternal tissues was unaffected by diabetes. Maternal diabetes increased IGF-2 mRNA in maternal adipose tissue but exhibited no effect in muscle or uterus. Expression of IGF-2 by maternal endometrium was decreased by diabetes. Maternal diabetes induced an increase in IGF-1 gene expression in muscle and placenta while causing an increase in IGF-2 expression in fetal liver and placenta. IGF-2 mRNA was lower in lung from fetuses of diabetic mothers than in controls. These results suggest that maternal diabetes alters IGF-1 and IGF-2 gene expression in specific tissues and differential regulation of these genes appears to exist in the mother and developing fetus

The quaternary structure of the recombinant bovine odorant-binding protein is modulated by chemical denaturants.

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Olga V Stepanenko

Full Text Available A large group of odorant-binding proteins (OBPs has attracted great scientific interest as promising building blocks in constructing optical biosensors for dangerous substances, such as toxic and explosive molecules. Native tissue-extracted bovine OBP (bOBP has a unique dimer folding pattern that involves crossing the α-helical domain in each monomer over the other monomer's β-barrel. In contrast, recombinant bOBP maintaining the high level of stability inherent to native tissue bOBP is produced in a stable native-like state with a decreased tendency for dimerization and is a mixture of monomers and dimers in a buffered solution. This work is focused on the study of the quaternary structure and the folding-unfolding processes of the recombinant bOBP in the absence and in the presence of guanidine hydrochloride (GdnHCl. Our results show that the recombinant bOBP native dimer is only formed at elevated GdnHCl concentrations (1.5 M. This process requires re-organizing the protein structure by progressing through the formation of an intermediate state. The bOBP dimerization process appears to be irreversible and it occurs before the protein unfolds. Though the observed structural changes for recombinant bOBP at pre-denaturing GdnHCl concentrations show a local character and the overall protein structure is maintained, such changes should be considered where the protein is used as a sensitive element in a biosensor system.

The use of supramolecular chemistry in dye delivery systems

International Nuclear Information System (INIS)

Merckel, Daniel Andrew Sturton

2002-01-01

This thesis reports an investigation into supramolecular recognition of the sulfate/ sulfonate oxoanionic group, a moiety present in the majority of reactive dyes. In the first section the problems associated with the use of reactive dyes in dyeing cotton fabrics together with a literature review of supramolecular approaches to anion recognition are discussed. Drawing on the current literature concerning anion recognition (in particular the recognition of phosphates), the main body of the thesis concerns the design and synthesis of several series ofC-shaped (tweezer) and tripodal potential sulfate/ sulfonate receptors. These receptors incorporate the H-bond donor groups guanidine and thiourea and to a lesser extent urea and amide functionalities. In addition the behaviour of potential tweezer-like receptor molecules based on s-triazine (derived from cyanuric chloride) has also been investigated. The sulfate/ sulfonate and related phosphonate association properties of these potential receptors have been studied. Particular emphasis has been placed on the solid-state supramolecular structures formed by these complexes as determined by single crystal X-ray structural studies, and several novel and revealing examples have been analysed in detail. NMR titration binding studies have also been undertaken in order to investigate the complexation behaviour of several receptors with ''model dye'' phosphonates and sulfonates in solution. In addition a number of single crystal X-ray crystallographic studies were undertaken for other members of the Grossel research group during the course of this work, and the results of these structural studies are also reported. (author)

Multiplexed detection of mycotoxins in foods with a regenerable array.

Science.gov (United States)

Ngundi, Miriam M; Shriver-Lake, Lisa C; Moore, Martin H; Ligler, Frances S; Taitt, Chris R

2006-12-01

The occurrence of different mycotoxins in cereal products calls for the development of a rapid, sensitive, and reliable detection method that is capable of analyzing samples for multiple toxins simultaneously. In this study, we report the development and application of a multiplexed competitive assay for the simultaneous detection of ochratoxin A (OTA) and deoxynivalenol (DON) in spiked barley, cornmeal, and wheat, as well as in naturally contaminated maize samples. Fluoroimmunoassays were performed with the Naval Research Laboratory array biosensor, by both a manual and an automated version of the system. This system employs evanescent-wave fluorescence excitation to probe binding events as they occur on the surface of a waveguide. Methanolic extracts of the samples were diluted threefold with buffer containing a mixture of fluorescent antibodies and were then passed over the arrays of mycotoxins immobilized on a waveguide. Fluorescent signals of the surface-bound antibody-antigen complexes decreased with increasing concentrations of free mycotoxins in the extract. After sample analysis was completed, surfaces were regenerated with 6 M guanidine hydrochloride in 50 mM glycine, pH 2.0. The limits of detection determined by the manual biosensor system were as follows: 1, 180, and 65 ng/g for DON and 1, 60, and 85 ng/g for OTA in cornmeal, wheat, and barley, respectively. The limits of detection in cornmeal determined with the automated array biosensor were 15 and 150 ng/g for OTA and DON, respectively.

A Suitable Polysulfide Electrolyte for CdSe Quantum Dot-Sensitized Solar Cells

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H. K. Jun

2013-01-01

Full Text Available A polysulfide liquid electrolyte is developed for the application in CdSe quantum dot-sensitized solar cells (QDSSCs. A solvent consisting of ethanol and water in the ratio of 8 : 2 by volume has been found as the optimum solvent for preparing the liquid electrolytes. This solvent ratio appears to give higher cell efficiency compared to pure ethanol or water as a solvent. Na2S and S give rise to a good redox couple in the electrolyte for QDSSC operation, and the optimum concentrations required are 0.5 M and 0.1 M, respectively. Addition of guanidine thiocyanate (GuSCN to the electrolyte further enhances the performance. The QDSSC with CdSe sensitized electrode prepared using 7 cycles of successive ionic layer adsorption and reaction (SILAR produces an efficiency of 1.41% with a fill factor of 44% on using a polysulfide electrolyte of 0.5 M Na2S, 0.1 M S, and 0.05 M GuSCN in ethanol/water (8 : 2 by volume under the illumination of 100 mW/cm2 white light. Inclusion of small amount of TiO2 nanoparticles into the electrolyte helps to stabilize the polysulfide electrolyte and thereby improve the stability of the CdSe QDSSC. The CdSe QDs are also found to be stable in the optimized polysulfide liquid electrolyte.

Activity based costing of diagnostic procedures at a nuclear medicine center of a tertiary care hospital.

Science.gov (United States)

Hada, Mahesh Singh; Chakravarty, Abhijit; Mukherjee, Partha

2014-10-01

Escalating health care expenses pose a new challenge to the health care environment of becoming more cost-effective. There is an urgent need for more accurate data on the costs of health care procedures. Demographic changes, changing morbidity profile, and the rising impact of noncommunicable diseases are emphasizing the role of nuclear medicine (NM) in the future health care environment. However, the impact of emerging disease load and stagnant resource availability needs to be balanced by a strategic drive towards optimal utilization of available healthcare resources. The aim was to ascertain the cost of diagnostic procedures conducted at the NM Department of a tertiary health care facility by employing activity based costing (ABC) method. A descriptive cross-sectional study was carried out over a period of 1 year. ABC methodology was utilized for ascertaining unit cost of different diagnostic procedures and such costs were compared with prevalent market rates for estimating cost effectiveness of the department being studied. The cost per unit procedure for various procedures varied from Rs. 869 (USD 14.48) for a thyroid scan to Rs. 11230 (USD 187.16) for a meta-iodo-benzyl-guanidine (MIBG) scan, the most cost-effective investigations being the stress thallium, technetium-99 m myocardial perfusion imaging (MPI) and MIBG scan. The costs obtained from this study were observed to be competitive when compared to prevalent market rates. ABC methodology provides precise costing inputs and should be used for all future costing studies in NM Departments.

Mycobacterium tuberculosis HspX/EsxS Fusion Protein: Gene Cloning, Protein Expression, and Purification in Escherichia coli.

Science.gov (United States)

Khademi, Farzad; Yousefi-Avarvand, Arshid; Derakhshan, Mohammad; Meshkat, Zahra; Tafaghodi, Mohsen; Ghazvini, Kiarash; Aryan, Ehsan; Sankian, Mojtaba

2017-10-01

The purpose of this study was to clone, express, and purify a novel multidomain fusion protein of Micobacterium tuberculosis (Mtb) in a prokaryotic system. An hspX/esxS gene construct was synthesized and ligated into a pGH plasmid, E. coli TOP10 cells were transformed, and the vector was purified. The vector containing the construct and pET-21b (+) plasmid were digested with the same enzymes and the construct was ligated into pET-21b (+). The accuracy of cloning was confirmed by colony PCR and sequencing. E. coli BL21 cells were transformed with the pET-21b (+)/hspX/esxS expression vector and protein expression was evaluated. Finally, the expressed fusion protein was purified on a Ni-IDA column and verified by SDS-PAGE and western blotting. The hspX/esxS gene construct was inserted into pET-21b (+) and recombinant protein expression was induced with IPTG in E. coli BL21 cells. Various concentrations of IPTG were tested to determine the optimum concentration for expression induction. The recombinant protein was expressed in insoluble inclusion bodies. Three molar guanidine HCl was used to solubilize the insoluble protein. An HspX/EsxS Mtb fusion protein was expressed in E. coli and the recombinant protein was purified. After immunological analysis, the HspX/EsxS fusion protein might be an anti-tuberculosis vaccine candidate in future clinical trial studies.

Analyzing the interaction of a herbal compound Andrographolide from Andrographis paniculata as a folklore against swine flu (H1N1

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Chandrabhan Seniya

2014-09-01

Full Text Available Objective: To find new bioactive molecules for the treatment of swine flu. Methods: The present study is an attempt to elucidate inhibition potential of andrographolide and its derivatives along with an associated binding mechanism through virtual screening and molecular docking simulation studies. Results: Our findings revealed structural conformation changes in 150 loop, secondary sialic acid binding site residues of ACZ97474 {Neuraminidase (A/Blore/NIV236/2009(H1N1}. Andrographolide have been identified as the highest binging energy of -1 0.88 Kcal/mol, 3 hydrogen bond interactions (Arg152, Lys150, and Gly197, total intermolecular energy of -12.07 Kcal/mol with bioactivity value (Ki of 10.59 nmol/L, while the Food and Drug Admistraton approved drug Oseltamivir and Zanamivir have shown 2 and 4 hydrogen bond interactions with binding energies of -6.28 Kcal/mol and -7.73Kcal/mol, respectively, which is higher than andrographolide. The guanidine group of Arg152 has binding affinities to the hydrophilic nature of the inhibitors (-OH and =O groups, as identified by docking of andrographolide (CID: 5318517 on neuraminidase. Conclusions: Hence, andrographolide has the potential to inhibit neuraminidase activity of H1N1 and may be used as an alternative medicinal therapy for swine flu positive patient. With potent antiviral activity and a potentially new mechanism of action, andrographolide may warrant further evaluation as a possible therapy for influenza.

Design of a hyperstable 60-subunit protein icosahedron

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Hsia, Yang; Bale, Jacob B.; Gonen, Shane; Shi, Dan; Sheffler, William; Fong, Kimberly K.; Nattermann, Una; Xu, Chunfu; Huang, Po-Ssu; Ravichandran, Rashmi; Yi, Sue; Davis, Trisha N.; Gonen, Tamir; King, Neil P.; Baker, David

2016-07-01

The icosahedron is the largest of the Platonic solids, and icosahedral protein structures are widely used in biological systems for packaging and transport. There has been considerable interest in repurposing such structures for applications ranging from targeted delivery to multivalent immunogen presentation. The ability to design proteins that self-assemble into precisely specified, highly ordered icosahedral structures would open the door to a new generation of protein containers with properties custom-tailored to specific applications. Here we describe the computational design of a 25-nanometre icosahedral nanocage that self-assembles from trimeric protein building blocks. The designed protein was produced in Escherichia coli, and found by electron microscopy to assemble into a homogenous population of icosahedral particles nearly identical to the design model. The particles are stable in 6.7 molar guanidine hydrochloride at up to 80 degrees Celsius, and undergo extremely abrupt, but reversible, disassembly between 2 molar and 2.25 molar guanidinium thiocyanate. The icosahedron is robust to genetic fusions: one or two copies of green fluorescent protein (GFP) can be fused to each of the 60 subunits to create highly fluorescent ‘standard candles’ for use in light microscopy, and a designed protein pentamer can be placed in the centre of each of the 20 pentameric faces to modulate the size of the entrance/exit channels of the cage. Such robust and customizable nanocages should have considerable utility in targeted drug delivery, vaccine design and synthetic biology.

Glucose-lowering effect of BTS 67 582.

Science.gov (United States)

Page, T; Bailey, C J

1997-12-01

1. The hypoglycaemic effect of BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl) guanidine fumarate) was studied in normal rats. 2. BTS 67 582 (100 mg kg(-1), p.o.) acutely lowered basal plasma glucose concentrations: onset within 1 h, maximum decrease of >40% at 2-3 h, and partial return to euglycaemia by 5 h. Plasma insulin concentrations were increased: onset within 30 min, maximum increase 3 fold at 1-2 h; returning to normal by 5 h. 3. BTS 67 582 (100 mg kg(-1)) increased (by 56%) the rate of disappearance of plasma glucose during an intravenous glucose tolerance test, accompanied by a 51% increase in insulin concentrations. 4. During hyperglycaemic clamp studies BTS 67 582 (100 mg kg(-1)) increased glucose utilization 3 fold. This was associated with a 3 fold increase in insulin concentrations, even in the presence of adrenaline at a dosage which inhibits glucose-induced insulin release. 5. When the insulin-releasing effect of BTS 67 582 (100 mg kg(-1)) was inhibited by infusion of somatostatin, there was no effect on glycaemia. 6. Insulin-dependent diabetic BB/S rats, which do not produce endogenous insulin, showed no effect of BTS 67 582 (100 mg kg(-1)) on plasma glucose concentrations in the presence or absence of exogenous insulin. 7. The results demonstrate an acute hypoglycaemic effect of BTS 67 582 which appears to result mainly from its potent insulin-releasing action.

Rat lingual lipase: partial purification, hydrolytic properties, and comparison with pancreatic lipase.

Science.gov (United States)

Roberts, I M; Montgomery, R K; Carey, M C

1984-10-01

We have partially purified lingual lipase from the serous glands of rat tongue. With a combination of Triton X-100 extraction or Triton X-114 phase-separation techniques, Bio-Bead SM-2 treatment, dialysis, and gel filtration on Sephadex G-200 or Sephacryl S-300, we obtained a sparingly soluble lipid-free protein demonstrating hydrolytic activity against triglycerides and negligible phospholipase or cholesteryl esterase activities. Compared with homogenate, specific activities of the enzyme were enriched 3- to 5-fold prior to gel filtration and 10-fold after gel filtration. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration under denaturing conditions (6 M guanidine X HCl or 0.1% sodium dodecyl sulfate) revealed one major glycoprotein band with Mr approximately 50,000. Gel filtration of the active enzyme in 0.1% Triton X-100 gave an Mr approximately 270,000-300,000, suggesting extensive self-aggregation. With both tributyrin and triolein, the pH optimum of the purified enzyme was 4.0 and activity extended from pH 2.0 to 8.0. In contrast to purified human pancreatic lipase, lingual lipase hydrolyzed triglyceride emulsions and mixed micelles stabilized with both short-chain (dihexanoyl) and long-chain (egg) lecithin and were inhibited only slightly (18-25%) by micellar concentrations of two common bile salts, taurodeoxycholate and taurocholate. Our results suggest that the hydrolysis of dietary fat by lingual lipase may extend from the pharynx through the esophagus and stomach and into the upper small intestine.

Activity based costing of diagnostic procedures at a nuclear medicine center of a tertiary care hospital

International Nuclear Information System (INIS)

Hada, Mahesh Singh; Chakravarty, Abhijit; Mukherjee, Partha

2014-01-01

Escalating health care expenses pose a new challenge to the health care environment of becoming more cost-effective. There is an urgent need for more accurate data on the costs of health care procedures. Demographic changes, changing morbidity profile, and the rising impact of noncommunicable diseases are emphasizing the role of nuclear medicine (NM) in the future health care environment. However, the impact of emerging disease load and stagnant resource availability needs to be balanced by a strategic drive towards optimal utilization of available healthcare resources. The aim was to ascertain the cost of diagnostic procedures conducted at the NM Department of a tertiary health care facility by employing activity based costing (ABC) method. A descriptive cross-sectional study was carried out over a period of 1 year. ABC methodology was utilized for ascertaining unit cost of different diagnostic procedures and such costs were compared with prevalent market rates for estimating cost effectiveness of the department being studied. The cost per unit procedure for various procedures varied from Rs. 869 (USD 14.48) for a thyroid scan to Rs. 11230 (USD 187.16) for a meta-iodo-benzyl-guanidine (MIBG) scan, the most cost-effective investigations being the stress thallium, technetium-99 m myocardial perfusion imaging (MPI) and MIBG scan. The costs obtained from this study were observed to be competitive when compared to prevalent market rates. ABC methodology provides precise costing inputs and should be used for all future costing studies in NM Departments

Carbonylation as a key reaction in anaerobic acetone activation by Desulfococcus biacutus.

Science.gov (United States)

Gutiérrez Acosta, Olga B; Hardt, Norman; Schink, Bernhard

2013-10-01

Acetone is activated by aerobic and nitrate-reducing bacteria via an ATP-dependent carboxylation reaction to form acetoacetate as the first reaction product. In the activation of acetone by sulfate-reducing bacteria, acetoacetate has not been found to be an intermediate. Here, we present evidence of a carbonylation reaction as the initial step in the activation of acetone by the strictly anaerobic sulfate reducer Desulfococcus biacutus. In cell suspension experiments, CO was found to be a far better cosubstrate for acetone activation than CO2. The hypothetical reaction product, acetoacetaldehyde, is extremely reactive and could not be identified as a free intermediate. However, acetoacetaldehyde dinitrophenylhydrazone was detected by mass spectrometry in cell extract experiments as a reaction product of acetone, CO, and dinitrophenylhydrazine. In a similar assay, 2-amino-4-methylpyrimidine was formed as the product of a reaction between acetoacetaldehyde and guanidine. The reaction depended on ATP as a cosubstrate. Moreover, the specific activity of aldehyde dehydrogenase (coenzyme A [CoA] acylating) tested with the putative physiological substrate was found to be 153 ± 36 mU mg(-1) protein, and its activity was specifically induced in extracts of acetone-grown cells. Moreover, acetoacetyl-CoA was detected (by mass spectrometry) after the carbonylation reaction as the subsequent intermediate after acetoacetaldehyde was formed. These results together provide evidence that acetoacetaldehyde is an intermediate in the activation of acetone by sulfate-reducing bacteria.

Protective value of immune responses developed in goats vaccinated with insoluble proteins from Sarcoptes Scabiei

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Simson Tarigan

2005-06-01

Full Text Available Vaccines developed from certain membrane proteins lining the lumen of arthropod’s gut have been demonstrated effective in the control of some arthropod ectoparasites. A similar approach could also be applied to Sarcoptes scabiei since this parasite also ingests its host immunoglobulins. To evaluate immune protection of the membrane proteins, insoluble mite proteins were fractionated by successive treatment in the solutions of 1.14 M NaCl, 2% SB 3-14 Zwitterion detergent, 6 M urea, 6 M guanidine-HCl and 5% SDS. Five groups of goats (6 or 7 goats per group were immunised respectively with the protein fractions. Vaccination was performed 6 times, each with a dosage of 250 μg proteins, and 3 week intervals between vaccination. Group 6 (7 goats received PBS and adjuvant only, and served as an unvaccinated control. One week after the last vaccination, all goats were challenged with 2000 live mites on the auricles. The development of lesions were examined at 1 day, 2 days, and then every week from week 1 to 8. All animals were bled and weighed every week, and at the end of the experiment, skin scrapings were collected to determine the mite burden. Antibody responses induced by vaccination and challenge were examined by ELISA and Western blotting. This experiment showed that vaccination with the insoluble-protein fractions resulted in the development of high level of specific antibodies but the responses did not have any protective value. The severity of lesions and mite burden in the vaccinated animals were not different from those in the unvaccinated control.

Correlation between antibiotic and biocide resistance in mesophilic and psychrotrophic Pseudomonas spp. isolated from slaughterhouse surfaces throughout meat chain production.

Science.gov (United States)

Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio; Abriouel, Hikmate

2015-10-01

The aim of this study was to evaluate biocide susceptibility in mesophilic and psychrotrophic pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which was representative of the region. To determine biocide resistance in pseudomonads, we determined for the first time the epidemiological cut-off values (ECOFFs) of benzalkonium, cetrimide, chlorhexidine, hexachlorophene, P3 oxonia, polyhexamethylene guanidine hydrochloride (PHMG), topax 66 and triclosan being generally very similar in different Pseudomonas spp. with some exceptions. Thus, resistance of pseudomonads was mainly shown to triclosan, and in lesser extent to cetrimide and benzalkonium chloride depending on the species, however they were highly susceptible to industrial formulations of biocides. By means of statistical analysis, positive correlations between antibiotics, biocides and both antimicrobials in pseudomonads were detected suggesting a co- or cross resistance between different antimicrobials in goat and lamb slaughterhouse environment. Cross-resistance between biocides and antibiotics in pseudomonads were especially detected between PHMG or triclosan and different antibiotics depending on the biocide and the population type. Thus, the use of those biocides as disinfectant in slaughterhouse zones must be carefully evaluated because of the selection pressure effect of antimicrobials on the emergence of resistant bacteria which could be spread to the consumer. It is noteworthy that specific industrial formulations such as topax 66 and oxonia P3 showed few correlations with antibiotics (none or 1-2 antibiotics) which should be taken into consideration for disinfection practices in goat and lamb slaughterhouse. Copyright © 2015 Elsevier Ltd. All rights reserved.

Guanicid and PHMG Toxicity Tests on Aquatic Organisms

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Eva Poštulková

2016-01-01

Full Text Available The emergence and development of new algicidal products is caused by the ever increasing popularity of garden ponds as well as the use of these products in the fisheries sector, especially for disposal of cyanobacteria and algae. Most frequent means of combating cyanobacteria and algae are applications of algicidal substances. Newly developed algaecides include Guanicid and polyhexamethylene guanidine hydrochloride (PHMG. The aim of the study was to identify toxic effects of Guanicid and PHMG on zebrafish (Danio rerio and green algae (Desmodesmus communis. We determined the acute toxicity in fish according to ČSN EN ISO 7346-1, and conducted the freshwater algae growth inhibition test according to ČSN ISO 8692 methodology. For inhibition tests with green algae we chose Guanicid and PHMG concentrations of 0.001, 0.005, and 0.010 ml/L. For fish short-term acute toxicity tests we chose Guanicid concentrations of 0.010, 0.050, 0.150, 0.200, 0.250, and 0.300 ml/L and PHMG concentrations of 0.010, 0.025, 0.050, 0.075, 0.100, and 0.125 ml/L. In case of zebrafish (Danio rerio, the LC50 value for Guanicid is 0.086 ml/L, while the LC50 value for PHMG is 0.043 ml/L. Effects of Guanicid on inhibition of green algae (Desmodesmus communis appear highly significant (p < 0.010 at a concentration of 0.010 ml/L. For PHMG, these effects are highly significant (p < 0.001 at concentrations of 0.005 and 0.010 ml/L in 48 hours.

Over-the-counter drugs block heart accumulation of MIBG

International Nuclear Information System (INIS)

Sherman, P.S.; Fisher, S.J.; Wieland, D.M.; Sisson, J.C.

1985-01-01

Previous work in the authors' laboratory using chemically sympathectomized animals showed that > 50% of meta-iodobenzyl-guanidine (MIBG) in the heart is localized in adrenergic nerves. In the present study, commonly used drugs known to alter the uptake and/or release of norepinephrine by adrenergic neurons have been evaluated for their effect on the biodistribution of MIBG. Pseudoephedrine (Sudafed), phenylpropanolamine (Dexatrim) and phenylephrine (Neosynephrine) were administered (5 mg/kg, i.p.) to rats; amphetamine was also evaluated (0.8mg/kg, i.p.). Thirty minutes later I-125-MIBG (0.2-0.4 Ci/mm) was injected i.v.; animals (N=3) were sacrificed 2 h following radiotracer. Compared to controls (N = 3), drug pretreatments resulted in large decreases in radiotracer concentration in adrenergic-rich tissues such as left atrium, left ventricle, spleen and parotid glands. Pseudoephedrine caused decreases (%) of 78, 57, 48 and 35 in the four tissues, respectively. Each of the four drugs caused a greater decrease in I-125-MIBG concentration in the left atrium than in the left ventricle. Comparative studies using H-3-norepinephrine are in progress. Entex, a nasal decongestant containing both phenylephrine and phenylpropanolamine, markedly diminished the heart and salivary gland accumulation of I-123-MIBG in a normal male volunteer. These preliminary studies suggest that commonly used sympathomimetic agents, including some over-the-counter preparations, decrease the accumulation of MIBG in adrenergic neurons. These results also suggest that patients should be carefully screened for drug usage prior to MIBG scintigraphy of the heart

Characterization of Actinomyces with genomic DNA fingerprints and rRNA gene probes.

Science.gov (United States)

Bowden, G; Johnson, J; Schachtele, C

1993-08-01

Cellular DNA from 25 Actinomyces naeslundii and Actinomyces viscosus strains belonging to the 7 taxonomic clusters of Fillery et al. (1978) and several unclustered strains was obtained by enzymatic and N-lauroylsarcosine/guanidine isothiocyanate treatment of whole cells, followed by extraction of the nucleic acid. The DNA samples were digested with restriction endonucleases BamHI or PvuII, and agarose gel electrophoresis was used to obtain DNA fingerprints. The DNA fragments were subjected to Southern blot hybridization with a digoxigenin-labeled cDNA probe transcribed from Escherichia coli 16S and 23S rRNA. The patterns of bands from genomic (DNA fingerprints) and rDNA fingerprints (ribotypes) were used for comparison between the taxonomic cluster strains and strains within clusters. Representative strains from each taxonomic cluster provided different BamHI DNA fingerprints and ribotype patterns with 3 to 9 distinct bands. Some strains within a cluster showed identical ribotype patterns with both endonucleases (A. naeslundii B120 and A. naeslundii B102 from cluster 3), while others showed the same pattern with BamHI but a different pattern with PvuII (A. naeslundii ATCC 12104 and 398A from cluster 5). A viscosus ATCC 15987 (cluster 7) and its parent strain T6 yielded identical fingerprint and ribotype patterns. The genomic diversity revealed by DNA fingerprinting and ribotyping demonstrates that these techniques, which do not require phenotypic expression, are suited for study of the oral ecology of the Actinomyces, and for epidemiological tracking of specific Actinomyces strains associated with caries lesions and sites of periodontal destruction.

Diagnostic impact of SPECT-CT in the assessment of endocrine tumors

International Nuclear Information System (INIS)

El Badaoui, A.; Clermont, H. de; Valli, N.; Caignon, J.M.; Fernandez, P.; Allard, M.; Barat, J.L.; Ducassou, D.; Clermont, H. de; Valli, N.; Caignon, J.M.; Fernandez, P.; Allard, M.; Barat, J.L.; Ducassou, D.; Clermont, H. de; Allard, M.

2008-01-01

Image fusion using single photon emission computed tomography - computed tomography (SPECT - CT) associates functional and morphological images. This study evaluates the added value of SPECT- CT, obtained with a hybrid SPECT- CT gamma camera, on anatomic localization and diagnostic impact in assessment of endocrine tumours and pheochromocytomas. Method: Six months prospective study was undertaken including 33 consecutive exams encompassing 20 Somatostatin Receptor Scintigraphies (S.R.S.) and 13 123 I-meta-iodo-benzyl-guanidine (Mibg) scans. Two experienced nuclear medicine physicians independently analysed independently planar and SPECT images in a first time, then, SPECT- CT fused images in a second time. They evaluated two parameters: SPECT- CT impact on anatomic localization (L.A.) and its diagnostic impact (I.D.). Each parameter was scored according three levels of evaluation. Results: An added value of SPECT- CT images was evidenced in 55% of cases on the anatomic localization and in 41% of the patients on the diagnostic impact. Therefore, a more important benefit was noted when SPECT was positive (L.A.: 90%; I.D.: 70%) than when it was negative (L.A.: 15%; I.D.: 8%). Furthermore, the added value proved higher for the S;R.S. compared to Mibg scans. Conclusion: SPECT- CT fusion images obtained by a hybrid system is more relevant to determine anatomic localization and more accurate than SPECT alone, particularly in the assessment of endocrine tumours. The added value of SPECT- CT seems to be lower for Mibg scans in the assessment of pheochromocytomas. (authors)

Sigma-1 receptor agonists directly inhibit Nav1.2/1.4 channels.

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Xiao-Fei Gao

Full Text Available (+-SKF 10047 (N-allyl-normetazocine is a prototypic and specific sigma-1 receptor agonist that has been used extensively to study the function of sigma-1 receptors. (+-SKF 10047 inhibits K(+, Na(+ and Ca2+ channels via sigma-1 receptor activation. We found that (+-SKF 10047 inhibited Na(V1.2 and Na(V1.4 channels independently of sigma-1 receptor activation. (+-SKF 10047 equally inhibited Na(V1.2/1.4 channel currents in HEK293T cells with abundant sigma-1 receptor expression and in COS-7 cells, which barely express sigma-1 receptors. The sigma-1 receptor antagonists BD 1063,BD 1047 and NE-100 did not block the inhibitory effects of (+-SKF-10047. Blocking of the PKA, PKC and G-protein pathways did not affect (+-SKF 10047 inhibition of Na(V1.2 channel currents. The sigma-1 receptor agonists Dextromethorphan (DM and 1,3-di-o-tolyl-guanidine (DTG also inhibited Na(V1.2 currents through a sigma-1 receptor-independent pathway. The (+-SKF 10047 inhibition of Na(V1.2 currents was use- and frequency-dependent. Point mutations demonstrated the importance of Phe(1764 and Tyr(1771 in the IV-segment 6 domain of the Na(V1.2 channel and Phe(1579 in the Na(V1.4 channel for (+-SKF 10047 inhibition. In conclusion, our results suggest that sigma-1 receptor agonists directly inhibit Na(V1.2/1.4 channels and that these interactions should be given special attention for future sigma-1 receptor function studies.

Increased Frequency of Rheumatoid Arthritis and Allergic Rhinitis among Pesticide Sprayers and Associations with Pesticide Use.

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Koureas, Michalis; Rachiotis, George; Tsakalof, Andreas; Hadjichristodoulou, Christos

2017-08-01

Objective : The aim of this study was to identify diseases linked with the pesticide sprayer occupation and explore possible associations with exposure history data. Methods : Α cross sectional study was conducted among pesticide sprayers ( n = 80) and the general population ( n = 90) in Thessaly (Greece). Medical history, demographic characteristics and detailed exposure history were recorded by conducting personal interviews. Lifetime exposure indicators were calculated for several pesticide chemical subclasses. Moreover, organophosphate metabolite levels were quantified in urine samples of all participants by using gas chromatography -mass spectrometry (GC-MS). Multinomial analysis was used to determine associations between occupational pesticide exposure and diseases or disorders. Results : In the pesticide sprayers group, significantly higher frequencies for rheumatoid arthritis (RA) and allergic rhinitis were observed compared with the control group ( p = 0.002 and p = 0.024 respectively). Within the pesticide sprayers group, high lifetime pesticide exposure was associated with increased risk for reporting RA (OR: 43.07 95% CI: 3.09-600.67) and allergic rhinitis (OR: 9.72 95% CI: 2.31-40.89), compared with low pesticide exposure. Exposure to organophsphate, guanidine and quinone pesticides were associated with RA while organophosphates, pyrethroids and paraquat were associated with allergic rhinitis. Despite the higher levels of certain pesticide metabolites observed among participants with rheumatoid arthritis, the differences were not statistically significant. One metabolite (diethylthiophosphate) was found to be significantly increased in allergic rhinitis cases ( p = 0.037). Conclusion s : The results from the current study suggest a possible association of occupational pesticide exposure with RA and allergic rhinitis that should be further investigated.

Aqueous Solutions of the Ionic Liquid 1-butyl-3-methylimidazolium Chloride Denature Proteins

International Nuclear Information System (INIS)

Baker, Gary A.; Heller, William T.

2009-01-01

As we advance our understanding, ionic liquids (ILs) are finding ever broader scope within the chemical sciences including, most recently, pharmaceutical, enzymatic, and bioanalytical applications. With examples of enzymatic activity reported in both neat ILs and in IL/water mixtures, enzymes are frequently assumed to adopt a quasi-native conformation, even if little work has been carried out to date toward characterizing the conformation, dynamics, active-site perturbation, cooperativity of unfolding transitions, free energy of stabilization, or aggregation/oligomerization state of enzymes in the presence of an IL solvent component. In this study, human serum albumin and equine heart cytochrome c were characterized in aqueous solutions of the fully water-miscible IL 1-butyl-3-methylimidazolium chloride, (bmim)Cl, by small-angle neutron and X-ray scattering. At (bmim)Cl concentrations up to 25 vol.%, these two proteins were found to largely retain their higher-order structures whereas both proteins become highly denatured at the highest IL concentration studied here (i.e., 50 vol.% (bmim)Cl). The response of these proteins to (bmim)Cl is analogous to their behavior in the widely studied denaturants guanidine hydrochloride and urea which similarly lead to random coil conformations at excessive molar concentrations. Interestingly, human serum albumin dimerizes in response to (bmim)Cl, whereas cytochrome c remains predominantly in monomeric form. These results have important implications for enzymatic studies in aqueous IL media, as they suggest a facile pathway through which biocatalytic activity can be altered in these nascent and potentially green electrolyte systems

Estimation of radiation dosage and transmutation effect of 14C involved in measuring rate of albumin synthesis with 14C-carbonate

International Nuclear Information System (INIS)

Yap, A.H.; Hafkenscheid, J.C.M.; Goossens, C.M.I.C.; Buys, W.C.A.M.; Binkhorst, R.A.; Van Tongeren, J.H.M.

1975-01-01

For direct measurement of the rate of albumin synthesis, Na 2 14 CO 3 was used intravenously. The assessment of the radiation hazard involved in the study was based on the knowledge of the minimum dose of Na 2 14 CO 3 necessary for a sufficient incorporation of 14 C in the guanidine-C of arginine in albumin to obtain measurable radioactivity. By measurement of expired 14 CO 2 and excreted 14 C-urea in the urine during a 5-hr period following intravenous administration of Na 2 14 CO 3 in five subjects, some quantitative data on 14 C retention and radiation dosage were obtained. In comparison with animal studies, the rate of expiration of 14 CO 2 in man is slower. About 50 percent of the total radioactivity injected was lost through the respiratory route in the first hour. The total amount of expired 14 C during the 5 hr of investigation was about 75 percent of the injected dose for the five subjects. The amount of 14 C excreted as urinary 14 C-urea during the 5 hr of investigation is very small in comparison with the expired 14 C; it was only about 0.5 percent of the dose injected. The total absorbed radiation dose after complete elimination of 14 C from the body was calculated with various assumptions. The extra risk of genetic damage due to disintegration of retained 14 C in comparison with that of natural 14 C in the body during 30 living years is about 50 percent. (U.S.)

The number and transmission of [PSI] prion seeds (Propagons in the yeast Saccharomyces cerevisiae.

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Lee J Byrne

Full Text Available Yeast (Saccharomyces cerevisiae prions are efficiently propagated and the on-going generation and transmission of prion seeds (propagons to daughter cells during cell division ensures a high degree of mitotic stability. The reversible inhibition of the molecular chaperone Hsp104p by guanidine hydrochloride (GdnHCl results in cell division-dependent elimination of yeast prions due to a block in propagon generation and the subsequent dilution out of propagons by cell division.Analysing the kinetics of the GdnHCl-induced elimination of the yeast [PSI+] prion has allowed us to develop novel statistical models that aid our understanding of prion propagation in yeast cells. Here we describe the application of a new stochastic model that allows us to estimate more accurately the mean number of propagons in a [PSI+] cell. To achieve this accuracy we also experimentally determine key cell reproduction parameters and show that the presence of the [PSI+] prion has no impact on these key processes. Additionally, we experimentally determine the proportion of propagons transmitted to a daughter cell and show this reflects the relative cell volume of mother and daughter cells at cell division.While propagon generation is an ATP-driven process, the partition of propagons to daughter cells occurs by passive transfer via the distribution of cytoplasm. Furthermore, our new estimates of n(0, the number of propagons per cell (500-1000, are some five times higher than our previous estimates and this has important implications for our understanding of the inheritance of the [PSI+] and the spontaneous formation of prion-free cells.

Metabolism of L-[guanidinooxy-14C]canavanine in the rat

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Thomas, D.A.; Rosenthal, G.A.

1987-01-01

The metabolism of L-canavanine, a nonprotein amino acid with significant antitumor effects, was investigated. L-Canavanine, provided at 2.0 g/kg, was supplemented with 5 microCi of L-[guanidinooxy- 14 C]canavanine (58 microCi/mumol) and administered iv, sc, or orally to female Sprague-Dawley rats weighing approximately 200 g. 14 C recovery in the urine at 24 hr was 83, 68, or 61%, respectively, of the administered dose. Another 5-8% of the 14 C was expired as 14 CO 2 . The gastrointestinal tract contained 21% of orally administered 14 C. Serum, feces, tissues, and de novo synthesized proteins only accounted for a few percent of the original dose by any administrative route. Analysis of the 14 C-containing urinary metabolites revealed that [ 14 C] urea accounted for 88% of the urinary radioactivity for an iv injection, 75% for sc administration, and 50% following an oral dose. By all routes of administration, [ 14 C]guanidine represented 5% of the radioactivity in the urine and [ 14 C]guanidinoacetic acid accounted for 2%. Serum and urine amino acid analysis showed a markedly elevated ornithine level. Basic amino acids such as histidine, lysine, and arginine were also higher in the urine. Plasma ammonia levels were determined following oral canavanine doses of 1.0, 2.0, and 4.0 g/kg. A rapid but transient elevation in plasma ammonia was observed only at the 4.0 g/kg dose. This indicates that elevated plasma ammonia is not a likely cause of canavanine toxicity at the drug concentrations used in this study

Cationic uremic toxins affect human renal proximal tubule cell functioning through interaction with the organic cation transporter.

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Schophuizen, Carolien M S; Wilmer, Martijn J; Jansen, Jitske; Gustavsson, Lena; Hilgendorf, Constanze; Hoenderop, Joost G J; van den Heuvel, Lambert P; Masereeuw, Rosalinde

2013-12-01

Several organic cations, such as guanidino compounds and polyamines, have been found to accumulate in plasma of patients with kidney failure due to inadequate renal clearance. Here, we studied the interaction of cationic uremic toxins with renal organic cation transport in a conditionally immortalized human proximal tubule epithelial cell line (ciPTEC). Transporter activity was measured and validated in cell suspensions by studying uptake of the fluorescent substrate 4-(4-(dimethylamino)styryl)-N-methylpyridinium-iodide (ASP(+)). Subsequently, the inhibitory potencies of the cationic uremic toxins, cadaverine, putrescine, spermine and spermidine (polyamines), acrolein (polyamine breakdown product), guanidine, and methylguanidine (guanidino compounds) were determined. Concentration-dependent inhibition of ASP(+) uptake by TPA, cimetidine, quinidine, and metformin confirmed functional endogenous organic cation transporter 2 (OCT2) expression in ciPTEC. All uremic toxins tested inhibited ASP(+) uptake, of which acrolein required the lowest concentration to provoke a half-maximal inhibition (IC50 = 44 ± 2 μM). A Dixon plot was constructed for acrolein using three independent inhibition curves with 10, 20, or 30 μM ASP(+), which demonstrated competitive or mixed type of interaction (K i = 93 ± 16 μM). Exposing the cells to a mixture of cationic uremic toxins resulted in a more potent and biphasic inhibitory response curve, indicating complex interactions between the toxins and ASP(+) uptake. In conclusion, ciPTEC proves a suitable model to study cationic xenobiotic interactions. Inhibition of cellular uptake transport was demonstrated for several uremic toxins, which might indicate a possible role in kidney disease progression during uremia.

Creatine salts provide neuroprotection even after partial impairment of the creatine transporter.

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Adriano, E; Garbati, P; Salis, A; Damonte, G; Millo, E; Balestrino, M

2017-01-06

Creatine, a compound that is critical for energy metabolism of nervous cells, crosses the blood-brain barrier (BBB) and the neuronal plasma membrane with difficulty, and only using its specific transporter. In the hereditary condition where the creatine transporter is defective (creatine transporter deficiency) there is no creatine in the brain, and administration of creatine is useless lacking the transporter. The disease is severe and incurable. Creatine-derived molecules that could cross BBB and plasma membrane independently of the transporter might be useful to cure this condition. Moreover, such molecules could be useful also in stroke and other brain ischemic conditions. In this paper, we investigated three creatine salts, creatine ascorbate, creatine gluconate and creatine glucose. Of these, creatine glucose was ineffective after transporter block with guanidine acetic acid (GPA) administration. Creatine ascorbate was not superior to creatine in increasing tissue creatine and phosphocreatine content after transporter impairment, however even after such impairment it delayed synaptic failure during anoxia. Finally, creatine gluconate was superior to creatine in increasing tissue content of creatine after transporter block and slowed down PS disappearance during anoxia, an effect that creatine did not have. These findings suggest that coupling creatine to molecules having a specific transporter may be a useful strategy in creatine transporter deficiency. In particular, creatine ascorbate has effects comparable to those of creatine in normal conditions, while being superior to it under conditions of missing or impaired creatine transporter. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

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Nevzat Selim Gokay

2016-01-01

Full Text Available The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg, inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg, or nitric oxide precursor L-arginine (200 mg/kg. After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P=0.044 positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders.

In vivo turnover of the basement membrane and other heparan sulfate proteoglycans of rat glomerulus

International Nuclear Information System (INIS)

Beavan, L.A.; Davies, M.; Couchman, J.R.; Williams, M.A.; Mason, R.M.

1989-01-01

The metabolic turnover of rat glomerular proteoglycans in vivo was investigated. Newly synthesized proteoglycans were labeled during a 7-h period after injecting sodium [35S]sulfate intraperitoneally. At the end of the labeling period a chase dose of sodium sulfate was given. Subsequently at defined times (0-163 h) the kidneys were perfused in situ with 0.01% cetylpyridinium chloride in phosphate-buffered saline to maximize the recovery of 35S-proteoglycans. Glomeruli were isolated from the renal cortex and analyzed for 35S-proteoglycans by autoradiographic, biochemical, and immunochemical methods. Grain counting of autoradiographs revealed a complex turnover pattern of 35S-labeled macromolecules, commencing with a rapid phase followed by a slower phase. Biochemical analysis confirmed the biphasic pattern and showed that the total population of [35S]heparan sulfate proteoglycans had a metabolic half-life (t1/2) of 20 and 60 h in the early and late phases, respectively. Heparan sulfate proteoglycans accounted for 80% of total 35S-proteoglycans, the remainder being chondroitin/dermatan sulfate proteoglycans. Whole glomeruli were extracted with 4% 3-[(cholamidopropyl)dimethy-lammonio]-1-propanesulfonate-4 M guanidine hydrochloride, a procedure which solubilized greater than 95% of the 35S-labeled macromolecules. Of these 11-13% was immunoprecipitated by an antiserum against heparan sulfate proteoglycan which, in immunolocalization experiments, showed specificity for staining the basement membrane of rat glomeruli. Autoradiographic analysis showed that 18% of total radioactivity present at the end of the labeling period was associated with the glomerular basement membrane

Agmatine protects against cell damage induced by NMDA and glutamate in cultured hippocampal neurons

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Wang, Wei-Ping; Iyo, Abiye H.; Miguel-Hidalgo, Javier; Regunathan, Soundar; Zhu, Meng-Yang

2010-01-01

Agmatine is a polyamine and has been considered as a novel neurotransmitter or neuromodulator in the central nervous system. In the present study, the neuroprotective effect of agmatine against cell damage caused by N-methyl-d-aspartate (NMDA) and glutamate was investigated in cultured rat hippocampal neurons. Lactate dehydrogenase (LDH) activity assay, β-tubulin III immunocytochemical staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end-labeling (TUNEL) assay were conducted to detect cell damage. Exposure of 12-day neuronal cultures of rat hippocampus to NMDA or glutamate for 1 h caused a concentration-dependent neurotoxicity, as indicated by the significant increase in released LDH activities. Addition of 100 µM agmatine into media ablated the neurotoxicity induced by NMDA or glutamate, an effect also produced by the specific NMDA receptor antagonist dizocilpine hydrogen maleate (MK801). Arcaine, an analog of agmatine with similar structure as agmatine, fully prevented the NMDA- or glutamate-induced neuronal damage. Spermine and putrescine, the endogenous polyamine and metabolic products of agmatine without the guanidine moiety of agmatine, failed to show this effect, indicating a structural relevance for this neuroprotection. Immunocytochemical staining and TUNEL assay confirmed the findings in the LDH measurement. That is, agmatine and MK801 markedly attenuated NMDA-induced neuronal death and significantly reduced TUNEL-positive cell numbers induced by exposure of cultured hippocampal neurons to NMDA. Taken together, these results demonstrate that agmatine can protect cultured hippocampal neurons from NMDA- or glutamate-induced excitotoxicity, through a possible blockade of the NMDA receptor channels or a potential anti-apoptotic property. PMID:16546145

ASIC3 Channels Integrate Agmatine and Multiple Inflammatory Signals through the Nonproton Ligand Sensing Domain

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Cao Hui

2010-12-01

Full Text Available Abstract Background Acid-sensing ion channels (ASICs have long been known to sense extracellular protons and contribute to sensory perception. Peripheral ASIC3 channels represent natural sensors of acidic and inflammatory pain. We recently reported the use of a synthetic compound, 2-guanidine-4-methylquinazoline (GMQ, to identify a novel nonproton sensing domain in the ASIC3 channel, and proposed that, based on its structural similarity with GMQ, the arginine metabolite agmatine (AGM may be an endogenous nonproton ligand for ASIC3 channels. Results Here, we present further evidence for the physiological correlation between AGM and ASIC3. Among arginine metabolites, only AGM and its analog arcaine (ARC activated ASIC3 channels at neutral pH in a sustained manner similar to GMQ. In addition to the homomeric ASIC3 channels, AGM also activated heteromeric ASIC3 plus ASIC1b channels, extending its potential physiological relevance. Importantly, the process of activation by AGM was highly sensitive to mild acidosis, hyperosmolarity, arachidonic acid (AA, lactic acid and reduced extracellular Ca2+. AGM-induced ASIC3 channel activation was not through the chelation of extracellular Ca2+ as occurs with increased lactate, but rather through a direct interaction with the newly identified nonproton ligand sensing domain. Finally, AGM cooperated with the multiple inflammatory signals to cause pain-related behaviors in an ASIC3-dependent manner. Conclusions Nonproton ligand sensing domain might represent a novel mechanism for activation or sensitization of ASIC3 channels underlying inflammatory pain-sensing under in vivo conditions.

Three distinct molecular species of proteoglycan synthesized by the rat limb bud at the prechondrogenic stage

International Nuclear Information System (INIS)

Matsui, F.; Oohira, A.; Shoji, R.; Nogami, H.

1989-01-01

To characterize proteoglycans in the prechondrogenic limb bud, proteoglycans were extracted with 4 M guanidine HCl containing a detergent and protease inhibitors from Day 13 fetal rat limb buds which had been labeled with [35S]sulfate for 3 h in vitro. About 90% of 35S-labeled proteoglycans was solubilized under the conditions used. The proteoglycan preparation was separated by DEAE-Sephacel column chromatography into three peaks; peak I eluted at 0.45 M NaCl concentration, peak II at 0.52 M, and peak III at 1.4 M. Peaks I and III were identified as proteoglycans bearing heparan sulfate side chains. The heparan sulfate proteoglycan in peak III was larger in hydrodynamic size than the proteoglycan in peak I. The heparan sulfate side chains of peak III proteoglycan were smaller in the size and more abundant in N-sulfated glucosamine than those of peak I proteoglycan. Peak II contained a chondroitin sulfate proteoglycan with a core protein of a doublet of Mr 550,000 and 500,000. The chondroitin sulfate proteoglycan was easily solubilized with a physiological salt solution and the heparan sulfate proteoglycan in peak I was partially solubilized with the physiological salt solution. The remainder of the proteoglycan in peak I and the heparan sulfate proteoglycan in peak III could be solubilized effectively only with a solution containing a detergent, such as nonanoyl-N-methylglucamide. This observation indicates the difference in the localization among these three proteoglycans in the developing rat limb bud

Covalent DNA-protein crosslinking occurs after hyperthermia and radiation

International Nuclear Information System (INIS)

Cress, A.E.; Bowden, G.T.

1983-01-01

Covalent DNA-protein crosslinks occur in exponentially growing mouse leukemia cells (L1210) after exposure to ionizing radiation. The amount of DNA-protein crosslinks as measured by a filter binding assay is dose dependent upon x irradiation. Although hyperthermia and radiation in combination are synergistic with respect to cell lethality, the combination does not result in an increase of DNA-protein crosslinks when assayed immediately following treatments. Hyperthermia (43 0 C/15 min) given prior to radiation dose not alter the radiation dose dependency of the amount of initial crosslinking. In addition, the amount of DNA-protein crosslinking produced by heat plus radiation is independent of the length of heating the cells at 43 0 C. The DNA-protein crosslinks produced y 50-Gy x ray alone are removed after 2 hr at 37 0 C. However, if hyperthermia (43 0 C/15 min) is given prior to 100-Gy x ray, the removal of DNA-protein crosslinks is delayed until 4.0 hr after radiation. Phospho-serine and phospho-threonine bonds are not produced with either radiation or the combination of hyperthermia plus radiation as judged by the resistance of the bonds to guanidine hydrochloride. However, hyperthermia plus radiation causes an increase in phosphate to nitrogen type bonding. These results show that radiation alone causes covalent DNA-protein crosslinks. Hyperthermia in combination with radiation does not increase the total amount of the crosslinks but delays the removal of the crosslinks and alters the distribution of the types of chemical bonding

Disruption of a hydrogen bond network in human versus spider monkey cytochrome c affects heme crevice stability.

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Goldes, Matthew E; Jeakins-Cooley, Margaret E; McClelland, Levi J; Mou, Tung-Chung; Bowler, Bruce E

2016-05-01

The hypothesis that the recent rapid evolution of primate cytochromes c, which primarily involves residues in the least stable Ω-loop (Ω-loop C, residues 40-57), stabilizes the heme crevice of cytochrome c relative to other mammals, is tested. To accomplish this goal, we have compared the properties of human and spider monkey cytochrome c and a set of four variants produced in the process of converting human cytochrome c into spider monkey cytochrome c. The global stability of all variants has been measured by guanidine hydrochloride denaturation. The stability of the heme crevice has been assessed with the alkaline conformational transition. Structural insight into the effects of the five amino acid substitutions needed to convert human cytochrome c into spider monkey cytochrome c is provided by a 1.15Å resolution structure of spider monkey cytochrome c. The global stability for all variants is near 9.0kcal/mol at 25°C and pH7, which is higher than that observed for other mammalian cytochromes c. The heme crevice stability is more sensitive to the substitutions required to produce spider monkey cytochrome c with decreases of up to 0.5 units in the apparent pKa of the alkaline conformational transition relative to human cytochrome c. The structure of spider monkey cytochrome c indicates that the Y46F substitution destabilizes the heme crevice by disrupting an extensive hydrogen bond network that connects three surface loops including Ω-loop D (residues 70-85), which contains the Met80 heme ligand. Copyright © 2015 Elsevier Inc. All rights reserved.

Axonal transport of proteoglycans to the goldfish optic tectum

International Nuclear Information System (INIS)

Ripellino, J.A.; Elam, J.S.

1988-01-01

The study addressed the question of whether 35 SO 4 labeled molecules that have been delivered to the goldfish optic nerve terminals by rapid axonal transport include soluble proteoglycans. For analysis, tectal homogenates were subfractionated into a soluble fraction (soluble after centrifugation at 105,000 g), a lysis fraction (soluble after treatment with hypotonic buffer followed by centrifugation at 105,000 g) and a final 105,000 g pellet fraction. The soluble fraction contained 25.7% of incorporated radioactivity and upon DEAE chromatography was resolved into a fraction of sulfated glycoproteins eluting at 0-0.32 M NaCl and containing 39.5% of total soluble label and a fraction eluting at 0.32-0.60 M NaCl containing 53.9% of soluble label. This latter fraction was included on columns of Sepharose CL-6B with or without 4 M guanidine and after pronase digestion was found to have 51% of its radioactivity contained in the glycosaminoglycans (GAGs) heparan sulfate and chondroitin (4 or 6) sulfate in the ratio of 70% to 30%. Mobility of both intact proteoglycans and constituent GAGs on Sepharose CL-6B indicated a size distribution that is smaller than has been observed for proteoglycans and GAGs from cultured neuronal cell lines. Similar analysis of lysis fraction, containing 11.5% of incorporated 35 SO 4 , showed a mixture of heparan sulfate and chondroitin sulfate containing proteoglycans, apparent free heparan sulfate and few, if any, sulfated glycoproteins. Overall, the results support the hypothesis that soluble proteoglycans are among the molecules axonally transported in the visual system

Prion replication without host adaptation during interspecies transmissions.

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Bian, Jifeng; Khaychuk, Vadim; Angers, Rachel C; Fernández-Borges, Natalia; Vidal, Enric; Meyerett-Reid, Crystal; Kim, Sehun; Calvi, Carla L; Bartz, Jason C; Hoover, Edward A; Agrimi, Umberto; Richt, Jürgen A; Castilla, Joaquín; Telling, Glenn C

2017-01-31

Adaptation of prions to new species is thought to reflect the capacity of the host-encoded cellular form of the prion protein (PrP C ) to selectively propagate optimized prion conformations from larger ensembles generated in the species of origin. Here we describe an alternate replicative process, termed nonadaptive prion amplification (NAPA), in which dominant conformers bypass this requirement during particular interspecies transmissions. To model susceptibility of horses to prions, we produced transgenic (Tg) mice expressing cognate PrP C Although disease transmission to only a subset of infected TgEq indicated a significant barrier to EqPrP C conversion, the resulting horse prions unexpectedly failed to cause disease upon further passage to TgEq. TgD expressing deer PrP C was similarly refractory to deer prions from diseased TgD infected with mink prions. In both cases, the resulting prions transmitted to mice expressing PrP C from the species of prion origin, demonstrating that transmission barrier eradication of the originating prions was ephemeral and adaptation superficial in TgEq and TgD. Horse prions produced in vitro by protein misfolding cyclic amplification of mouse prions using horse PrP C also failed to infect TgEq but retained tropism for wild-type mice. Concordant patterns of neuropathology and prion deposition in susceptible mice infected with NAPA prions and the corresponding prion of origin confirmed preservation of strain properties. The comparable responses of both prion types to guanidine hydrochloride denaturation indicated this occurs because NAPA precludes selection of novel prion conformations. Our findings provide insights into mechanisms regulating interspecies prion transmission and a framework to reconcile puzzling epidemiological features of certain prion disorders.

Choline transport via choline transporter-like protein 1 in conditionally immortalized rat syncytiotrophoblast cell lines TR-TBT.

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Lee, N-Y; Choi, H-M; Kang, Y-S

2009-04-01

Choline is an essential nutrient for phospholipids and acetylcholine biosynthesis in normal development of fetus. In the present study, we investigated the functional characteristics of choline transport system and inhibitory effect of cationic drugs on choline transport in rat conditionally immortalized syncytiotrophoblast cell line (TR-TBT). Choline transport was weakly Na(+) dependent and significantly influenced by extracellular pH and by membrane depolarization. The transport process of choline is saturable with Michaelis-Menten constants (K(m)) of 68microM and 130microM in TR-TBT 18d-1 and TR-TBT 18d-2 respectively. Choline uptake in the cells was inhibited by unlabeled choline and hemicholinium-3 as well as various organic cations including guanidine, amiloride and acetylcholine. However, the prototypical organic cation tetraethylammonium and cimetidine showed very little inhibitory effect of choline uptake in TR-TBT cells. RT-PCR revealed that choline transporter-like protein 1 (CTL1) and organic cation transporter 2 (OCT2) are expressed in TR-TBT cells. The transport properties of choline in TR-TBT cells were similar or identical to that of CTL1 but not OCT2. CTL1 was also detected in human placenta. In addition, several cationic drugs such as diphenhydramine and verapamil competitively inhibited choline uptake in TR-TBT 18d-1 with K(i) of 115microM and 55microM, respectively. Our results suggest that choline transport system, which has intermediate affinity and weakly Na(+) dependent, in TR-TBT seems to occur through a CTL1 and this system may have relevance with the uptake of pharmacologically important organic cation drugs.

A novel pyrimidine derivative as a fluorescent chemosensor for highly selective detection of aluminum (III) in aqueous media.

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Suryawanshi, Vishwas D; Gore, Anil H; Dongare, Pravin R; Anbhule, Prashant V; Patil, Shivajirao R; Kolekar, Govind B

2013-10-01

An efficient fluorescent chemosensor Al(3+) receptor based on pyrimidine derivative,2-amino-6-hydroxy-4-(4-N,N-dimethylaminophenyl)-pyrimidine-5-carbonitrile (DMAB), has been synthesized by three-component condensation of aromatic aldehyde, ethyl cyanoacetate and guanidine hydrochloride in ethanol under alkaline medium. High selectivity and sensitivity of DMAB towards Aluminum ion (Al(3+)) in water: ethanol and acetate buffer at pH 4.0 makes it suitable to detect Al(3+) with steady-state UV-vis and fluorescence spectroscopy. Method shows good selectivity towards Al(3+) over other coexisting metal ions tested, viz. Fe(2+), Ni(2+), Cu(2+), Co(2+), Pb(2+), Sb(3+), Na(+), Ca(2+), Mg(2+), Zn(2+), Hg(2+), Ba(2+), Cd(2+) and K(+). A good linearity between the Stern-Volmer plots of F0/F versus concentration of Al(3+) was observed over the range from 10 to 60 μg mL(-1) with correlation coefficient of 0.991. The accuracy and reliability of the method were further confirmed by recovery studies via standard addition method with percent recoveries in the range of 101.03-103.44% and lowest detection limit (LOD=7.35 μg mL(-1)) for Al(3+) was established. This method may offer a new cost-effective, rapid, and simple key to the inspection of Al(3+) ions in water samples in the presence of a complex matrix and can be capable of evaluating the exceeding standard of Al(3+) in environmental water samples. The probable mechanism for fluorescence quenching was also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Identification of liquid-phase decomposition species and reactions for guanidinium azotetrazolate

International Nuclear Information System (INIS)

Kumbhakarna, Neeraj R.; Shah, Kaushal J.; Chowdhury, Arindrajit; Thynell, Stefan T.

2014-01-01

Highlights: • Guanidinium azotetrazolate (GzT) is a high-nitrogen energetic material. • FTIR spectroscopy and ToFMS spectrometry were used for species identification. • Quantum mechanics was used to identify transition states and decomposition pathways. • Important reactions in the GzT liquid-phase decomposition process were identified. • Initiation of decomposition occurs via ring opening, releasing N 2 . - Abstract: The objective of this work is to analyze the decomposition of guanidinium azotetrazolate (GzT) in the liquid phase by using a combined experimental and computational approach. The experimental part involves the use of Fourier transform infrared (FTIR) spectroscopy to acquire the spectral transmittance of the evolved gas-phase species from rapid thermolysis, as well as to acquire spectral transmittance of the condensate and residue formed from the decomposition. Time-of-flight mass spectrometry (ToFMS) is also used to acquire mass spectra of the evolved gas-phase species. Sub-milligram samples of GzT were heated at rates of about 2000 K/s to a set temperature (553–573 K) where decomposition occurred under isothermal conditions. N 2 , NH 3 , HCN, guanidine and melamine were identified as products of decomposition. The computational approach is based on using quantum mechanics for confirming the identity of the species observed in experiments and for identifying elementary chemical reactions that formed these species. In these ab initio techniques, various levels of theory and basis sets were used. Based on the calculated enthalpy and free energy values of various molecular structures, important reaction pathways were identified. Initiation of decomposition of GzT occurs via ring opening to release N 2

Environmental Factors Modulating the Stability and Enzymatic Activity of the Petrotoga mobilis Esterase (PmEst.

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Jose L S Lopes

Full Text Available Enzymes isolated from thermophilic organisms found in oil reservoirs can find applications in many fields, including the oleochemical, pharmaceutical, bioenergy, and food/dairy industries. In this study, in silico identification and recombinant production of an esterase from the extremophile bacteria Petrotoga mobilis (designated PmEst were performed. Then biochemical, bioinformatics and structural characterizations were undertaken using a combination of synchrotron radiation circular dichroism (SRCD and fluorescence spectroscopies to correlate PmEst stability and hydrolytic activity on different substrates. The enzyme presented a high Michaelis-Menten constant (KM 0.16 mM and optimum activity at ~55°C for p-nitrophenyl butyrate. The secondary structure of PmEst was preserved at acid pH, but not under alkaline conditions. PmEst was unfolded at high concentrations of urea or guanidine through apparently different mechanisms. The esterase activity of PmEst was preserved in the presence of ethanol or propanol and its melting temperature increased ~8°C in the presence of these organic solvents. PmEst is a mesophilic esterase with substrate preference towards short-to medium-length acyl chains. The SRCD data of PmEst is in agreement with the prediction of an α/β protein, which leads us to assume that it displays a typical fold of esterases from this family. The increased enzyme stability in organic solvents may enable novel applications for its use in synthetic biology. Taken together, our results demonstrate features of the PmEst enzyme that indicate it may be suitable for applications in industrial processes, particularly, when the use of polar organic solvents is required.

Aggregation-primed molten globule conformers of the p53 core domain provide potential tools for studying p53C aggregation in cancer.

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Pedrote, Murilo M; de Oliveira, Guilherme A P; Felix, Adriani L; Mota, Michelle F; Marques, Mayra de A; Soares, Iaci N; Iqbal, Anwar; Norberto, Douglas R; Gomes, Andre M O; Gratton, Enrico; Cino, Elio A; Silva, Jerson L

2018-05-31

The functionality of the tumor suppressor p53 is altered in more than 50% of human cancers, and many individuals with cancer exhibit amyloid-like buildups of aggregated p53. An understanding of what triggers the pathogenic amyloid conversion of p53 is required for the further development of cancer therapies. Here, perturbation of the p53 core domain (p53C) with sub-denaturing concentrations of guanidine hydrochloride and high hydrostatic pressure revealed native-like molten globule (MG) states, a subset of which were highly prone to amyloidogenic aggregation. We found that MG conformers of p53C, likely representing population-weighted averages of multiple states, have different volumetric properties, as determined by pressure perturbation and size-exclusion chromatography. We also found that they bind the fluorescent dye 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) and have a native-like tertiary structure that occludes the single Trp residue in p53. Fluorescence experiments revealed conformational changes of the single Trp and Tyr residues before p53 unfolding and the presence of MG conformers, some of which were highly prone to aggregation. P53C exhibited marginal unfolding cooperativity, which could be modulated from unfolding to aggregation pathways with chemical or physical forces. We conclude that trapping amyloid precursor states in solution is a promising approach for understanding p53 aggregation in cancer. Our findings support the use of single-Trp fluorescence as a probe for evaluating p53 stability, effects of mutations, and the efficacy of therapeutics designed to stabilize p53. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Roles of N- and C-terminal domains in the ligand-binding properties of cytoglobin.

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Hanai, Shumpei; Tsujino, Hirofumi; Yamashita, Taku; Torii, Ryo; Sawai, Hitomi; Shiro, Yoshitsugu; Oohora, Koji; Hayashi, Takashi; Uno, Tadayuki

2018-02-01

Cytoglobin (Cygb) is a member of the hexacoordinated globin protein family and is expressed ubiquitously in rat and human tissues. Although Cygb is reportedly upregulated under hypoxic conditions both in vivo and in vitro, suggesting a physiological function to protect cells under hypoxic/ischemic conditions by scavenging reactive oxygen species or by signal transduction, the mechanisms associated with this function have not been fully elucidated. Recent studies comparing Cygbs among several species suggest that mammalian Cygbs show a distinctly longer C-terminal domain potentially involved in unique physiological functions. In this study, we prepared human Cygb mutants (ΔC, ΔN, and ΔNC) with either one or both terminal domains truncated and investigated the enzymatic functions and structural features by spectroscopic methods. Evaluation of the superoxide-scavenging activity between Cygb variants showed that the ΔC and ΔNC mutants exhibited slightly higher activity involving superoxide scavenging as compared with wild-type Cygb. Subsequent experiments involving ligand titration, flash photolysis, and resonance Raman spectroscopic studies suggested that the truncation of the C- and N-terminal domains resulted in less effective to dissociation constants and binding rates for carbon monoxide, respectively. Furthermore, structural stability was assessed by guanidine hydrochloride and revealed that the C-terminal domain might play a vital role in improving structure, whereas the N-terminal domain did not exert a similar effect. These findings indicated that long terminal domains could be important not only in regulating enzymatic activity but also for structural stability, and that the domains might be relevant to other hypothesized physiological functions for Cygb. Copyright © 2017 Elsevier Inc. All rights reserved.

Characterization of Novel Fusaricidins Produced by Paenibacillus polymyxa-M1 Using MALDI-TOF Mass Spectrometry

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Vater, Joachim; Niu, Ben; Dietel, Kristin; Borriss, Rainer

2015-09-01

Paenibacillus polymyxa-M1 is a potent producer of bioactive compounds, such as lipopeptides, polyketides, and lantibiotics of biotechnological and medical interest. Genome sequencing revealed nine gene clusters for nonribosomal biosynthesis of such agents. Here we report on the investigation of the fusaricidins, a complex of cyclic lipopeptides containing 15-guanidino-3-hydroxypentadecanoic acid (GHPD) as fatty acid component by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). More than 20 variants of these compounds were detected and characterized in detail. Mass spectrometric sequence analysis was performed by MALDI-LIFT-TOF/TOF fragment analysis. The obtained product ion spectra show a specific processing in the fatty acid part. GHPD is cleaved between the α- and ß-position yielding two fragments a and b, one bearing the end-standing guanidine group and another one comprising the residual two C-atoms of GHPD with the attached peptide moiety. The complete sequence of all fusaricidins was derived from sets of bn- and yn-ions. The fusaricidin complex can be divided into four lipopeptide families, three of them showing variations of the amino acid in position 3, Val or Ile for the first and Tyr or Phe for families 2 and 3, respectively. A collection of novel fusaricidins was detected differing from those of families 1-3 by an additional residue of 71 Da (family 4). LIFT-TOF/TOF fragment spectra of these species imply that in their peptide moiety, an Ala-residue is attached by an ester bond to the free hydroxyl group of Thr4. More than 10 novel fusaricidins were characterized mass spectrometrically.

Systematic mutagenesis method for enhanced production of bacitracin by Bacillus licheniformis mutant strain UV-MN-HN-6

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Muhammad Nauman Aftab

2012-03-01

Full Text Available The purpose of the current study was intended to obtain the enhanced production of bacitracin by Bacillus licheniformis through random mutagenesis and optimization of various parameters. Several isolates of Bacillus licheniformis were isolated from local habitat and isolate designated as GP-35 produced maximum bacitracin production (14±0.72 IU ml-1. Bacitracin production of Bacillus licheniformis GP-35 was increased to 23±0.69 IU ml-1 after treatment with ultraviolet (UV radiations. Similarly, treatment of vegetative cells of GP-35 with chemicals like N-methyl N'-nitro N-nitroso guanidine (MNNG and Nitrous acid (HNO2 increased the bacitracin production to a level of 31±1.35 IU ml-1 and 27±0.89 IU ml-1 respectively. Treatment of isolate GP-35 with combined effect of UV and chemical treatment yield significantly higher titers of bacitracin with maximum bacitracin production of 41.6±0.92 IU ml-1. Production of bacitracin was further enhanced (59.1±1.35 IU ml-1 by optimization of different parameters like phosphate sources, organic acids as well as temperature and pH. An increase of 4.22 fold in the production of bacitracin after mutagenesis and optimization of various parameters was achieved in comparison to wild type. Mutant strain was highly stable and produced consistent yield of bacitracin even after 15 generations. On the basis of kinetic variables, notably Yp/s (IU/g substrate, Yp/x (IU/g cells, Yx/s (g/g, Yp/s, mutant strain B. licheniformis UV-MN-HN-6 was found to be a hyperproducer of bacitracin.

Reduction of β-amyloid accumulation by reticulon 3 in transgenic mice.

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Araki, Wataru; Oda, Akiko; Motoki, Kazumi; Hattori, Kotaro; Itoh, Masayuki; Yuasa, Shigeki; Konishi, Yoshihiro; Shin, Ryong-Woon; Tamaoka, Akira; Ogino, Koichi

2013-02-01

Inhibition of the β-secretase, BACE1, which cleaves amyloid precursor protein (APP) to produce β-amyloid protein (Aβ), is thought to be a feasible therapeutic strategy for Alzheimer's disease. Reticulon (RTN) proteins such as RTN3 have been identified as membrane proteins that interact with BACE1 and inhibit its Aβ-generating activity. In this study, we investigated whether RTN3 can regulate Aβ production in vivo, using transgenic (Tg) mice expressing APP with Swedish and London mutations (APP Tg mice) and those expressing RTN3; the latter mice showed ~1.4-fold higher expression levels of RTN3 protein in the cerebral cortex than non-Tg controls. We analyzed the brains of single APP Tg and double APP/RTN3 Tg mice at the age of approximately 15 months. The levels of secreted APP-β, a direct BACE1 cleavage product of APP, in Tris-soluble fraction were considerably reduced in the hippocampus and cerebral cortex of APP/RTN3 Tg mice relative to those in APP Tg mice. Immunohistochemical analyses demonstrated that Aβ burden and plaques were significantly (by approximately 50%) decreased in both the hippocampus and cerebral cortex of double Tg mice compared to APP Tg mice. Furthermore, the levels of guanidine-soluble Aβ40 and Aβ42 in these brain regions of APP/RTN3 Tg mice were relatively lower than those in APP Tg mice. These findings indicate that even a small increase in RTN3 expression exerts suppressive effects on amyloidogenic processing of APP and Aβ accumulation through modulation of BACE1 activity in vivo, and suggest that induction of RTN3 might be an effective therapeutic strategy against Alzheimer's disease.

Efficiency of boiling and four other methods for genomic DNA extraction of deteriorating spore-forming bacteria from milk

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Jose Carlos Ribeiro Junior

2016-10-01

Full Text Available The spore-forming microbiota is mainly responsible for the deterioration of pasteurized milk with long shelf life in the United States. The identification of these microorganisms, using molecular tools, is of particular importance for the maintenance of the quality of milk. However, these molecular techniques are not only costly but also labor-intensive and time-consuming. The aim of this study was to compare the efficiency of boiling in conjunction with four other methods for the genomic DNA extraction of sporulated bacteria with proteolytic and lipolytic potential isolated from raw milk in the states of Paraná and Maranhão, Brazil. Protocols based on cellular lysis by enzymatic digestion, phenolic extraction, microwave-heating, as well as the use of guanidine isothiocyanate were used. This study proposes a method involving simple boiling for the extraction of genomic DNA from these microorganisms. Variations in the quality and yield of the extracted DNA among these methods were observed. However, both the cell lysis protocol by enzymatic digestion (commercial kit and the simple boiling method proposed in this study yielded sufficient DNA for successfully carrying out the Polymerase Chain Reaction (PCR of the rpoB and 16S rRNA genes for all 11 strains of microorganisms tested. Other protocols failed to yield sufficient quantity and quality of DNA from all microorganisms tested, since only a few strains have showed positive results by PCR, thereby hindering the search for new microorganisms. Thus, the simple boiling method for DNA extraction from sporulated bacteria in spoiled milk showed the same efficacy as that of the commercial kit. Moreover, the method is inexpensive, easy to perform, and much less time-consuming.

A high molecular weight proteoglycan is differentially expressed during development of the mollusc Concholepas concholepas (Mollusca; Gastropoda; Muricidae).

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Brandan, E; González, M; Inestrosa, N C; Tremblay, C; Urrea, R

1992-12-15

Incorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE-Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S-500 and SDS-PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 x 10(6)). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. The epitope recognized by this mAb seems to be present in the core protein of the PG. Both the extent of sulfation and the presence of different sulfated species of PGs were evaluated during the development of this mollusc. A twelvefold increase in the incorporation of sulfate to PGs per milligram of protein was found in veliger larvae compared to blastula-glastula stages. This change correlated well with the differential expression of the sulfated PG present in peak I. Biochemical and immunological analysis indicate that high levels of this PG are found in veliger and trocophore larvae in comparison with blastula-gastrula and early juveniles.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional properties of the recombinant kringle-2 domain of tissue plasminogen activator produced in Escherichia coli

International Nuclear Information System (INIS)

Wilhelm, O.G.; Jaskunas, S.R.; Vlahos, C.J.; Bang, N.U.

1990-01-01

The kringle-2 domain (residues 176-262) of tissue-type plasminogen activator (t-PA) was cloned and expressed in Escherichia coli. The recombinant peptide, which concentrated in cytoplasmic inclusion bodies, was isolated, solubilized, chemically refolded, and purified by affinity chromatography on lysine-Sepharose to apparent homogeneity. [35S]Cysteine-methionine-labeled polypeptide was used to study the interactions of kringle-2 with lysine, fibrin, and plasminogen activator inhibitor-1. The kringle-2 domain bound to lysine-Sepharose and to preformed fibrin with a Kd = 104 +/- 6.2 microM (0.86 +/- 0.012 binding site) and a Kd = 4.2 +/- 1.05 microM (0.80 +/- 0.081 binding site), respectively. Competition experiments and direct binding studies showed that the kringle-2 domain is required for the formation of the ternary t-PA-plasminogen-intact fibrin complex and that the association between the t-PA kringle-2 domain and fibrin does not require plasmin degradation of fibrin and exposure of new COOH-terminal lysine residues. We also observed that kringle-2 forms a complex with highly purified guanidine-activated plasminogen activator inhibitor-1, dissociable by 0.2 M epsilon-aminocaproic acid. The kringle-2 polypeptide significantly inhibited tissue plasminogen activator/plasminogen activator inhibitor-1 interaction. The kringle-2 domain bound to plasminogen activator inhibitor-1 in a specific and saturable manner with a Kd = 0.51 +/- 0.055 microM (0.35 +/- 0.026 binding site). Therefore, the t-PA kringle-2 domain is important for the interaction of t-PA not only with fibrin, but also with plasminogen activator inhibitor-1 and thus represents a key structure in the regulation of fibrinolysis

[Comparison of Physico-chemical Aspects between E. coli and Human Dihydrofolate Reductase: an Equilibrium Unfolding Study].

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Thapliyal, Charu; Jain, Neha; Chaudhuri, Pratima

2015-01-01

A protein, differing in origin, may exhibit variable physicochemical behaviour, difference in sequence homology, fold and function. Thus studying structure-function relationship of proteins from altered sources is meaningful in the sense that it may give rise to comparative aspects of their sequence-structure-function relationship. Dihydrofolate reductase is an enzyme involved in cell cycle regulation. It is a significant enzyme as.a target for developing anticancer drugs. Hence, detailed understanding of structure-function relationships of wide variants of the enzyme dihydrofolate reductase would be important for developing an inhibitor or an antagonist against the enzyme involved in the cellular developmental processes. In this communication, we have reported the comparative structure-function relationship between E. coli and human dihydrofolate reductase. The differences in the unfolding behaviour of these two proteins have been investigated to understand various properties of these two proteins like relative' stability differences and variation in conformational changes under identical denaturing conditions. The equilibrium unfolding mechanism of dihydrofolate reductase proteins using guanidine hydrochloride as a denaturant in the presence of various types of osmolytes has been monitored using loss in enzymatic activity, intrinsic tryptophan fluorescence and an extrinsic fluorophore 8-anilino-1-naphthalene-sulfonic acid as probes. It has been observed that osmolytes, such as 1M sucrose, and 30% glycerol, provided enhanced stability to both variants of dihydrofolate reductase. Their level of stabilisation has been observed to be dependent on intrinsic protein stability. It was observed that 100 mM proline does not show any 'significant stabilisation to either of dihydrofolate reductases. In the present study, it has been observed that the human protein is relatively less stable than the E.coli counterpart.

Comparison of gene expression profiles of HepG2 cells exposed to Crambescins C1 and A1

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María R. Sánchez

2014-06-01

Full Text Available Crambescins are guanidine alkaloids firstly isolated in the early 90s from the encrusting Mediterranean sponge Crambe crambe (Schmidt, 1862 (Bondu et al., 2012, Laville et al., 2009, Berlinck et al., 1990. C. crambe derivatives are divided in two families named crambescins and crambescidins (Gerlinck et al., 1992. Although data on the bioactivity of these compounds is scarce, crambescidins have recognized cytotoxic, antifungal, antioxidant, antimicrobial and antiviral activities (Buscema and Van de Vyver, 1985, Jares-Erijman., 1998, Olszewski et al., 2004, Lazaro et al., 2006, Suna et al., 2007, AOKI et al., 2004. Recently we have carefully evaluated the cytotoxic activity of C816 over several human tumor cell types and characterized some of the cellular mechanisms responsible of the anti-proliferative effect of this compound on human liver-derived tumor cells (Rubiolo et al., 2013. Taking this into account, and to better understand the mechanism of action of crambescins and their potential as therapeutic agents, we made a comparative gene expression profiling of HepG2 cells after crambescin C1 (C1 and crambescin A1 (CA1 exposures. Results have shown that C1 induces genes involved in sterol and glucose metabolisms and metabolism involving growth factors. It also down regulates genes mainly involved in cell cycle control, DNA replication, recombination and repair, and drug metabolism. Flow cytometry assays revealed that C1 produces a G0/G1 arrest in HepG2 cell cycle progression. CA1 also down-regulates genes involved in cell cycle regulation, DNA recombination and pathways related to tumor cells proliferation with lower potency when compared to C1.

Residues Phe103 and Phe149 are critical for the co-chaperone activity of Bacillus licheniformis GrpE.

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Lin, Min-Guan; Chi, Meng-Chun; Chen, Bo-En; Wang, Tzu-Fan; Lo, Huei-Fen; Lin, Long-Liu

2015-01-01

A tryptophan-free Bacillus licheniformis nucleotide exchange factor (BlGrpE) and its Trp mutants (F70W, F103W, F149W, F70/103W, F70/149W, F103/149W and F70/103/149W) were over-expressed and purified to near homogeneity. Simultaneous addition of B. licheniformis DnaJ, NR-peptide and individual variants synergistically stimulated the ATPase activity of a recombinant DnaK (BlDnaK) from the same bacterium by 3.1-14.7-fold, which are significantly lower than the synergistic stimulation (18.9-fold) of BlGrpE. Protein-protein interaction analysis revealed that Trp mutants relevant to amino acid positions 103 and 149 lost the ability to bind BlDnaK. Circular dichroism measurements indicate that F70W displayed a comparable level of secondary structure to that of BlGrpE, and the wild-type protein and the Trp mutants as well all experienced a reversible behavior of thermal denaturation. Guanidine hydrochloride (GdnHCl)-induced unfolding transition for BlGrpE was calculated to be 1.25 M corresponding to ΔG(N-U) of 4.29 kcal/mol, whereas the unfolding transitions of mutant proteins were in the range of 0.77-1.31 M equivalent to ΔG(N-U) of 2.41-4.14 kcal/mol. Taken together, the introduction of tryptophan residue, especially at positions 103 and 149, into the primary structure of BlGrpE has been proven to be detrimental to structural integrity and proper function of the protein. Copyright © 2014 Elsevier B.V. All rights reserved.

Lysine and the Na+/K+ Selectivity in Mammalian Voltage-Gated Sodium Channels.

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Yang Li

Full Text Available Voltage-gated sodium (Nav channels are critical in the generation and transmission of neuronal signals in mammals. The crystal structures of several prokaryotic Nav channels determined in recent years inspire the mechanistic studies on their selection upon the permeable cations (especially between Na+ and K+ ions, a property that is proposed to be mainly determined by residues in the selectivity filter. However, the mechanism of cation selection in mammalian Nav channels lacks direct explanation at atomic level due to the difference in amino acid sequences between mammalian and prokaryotic Nav homologues, especially at the constriction site where the DEKA motif has been identified to determine the Na+/K+ selectivity in mammalian Nav channels but is completely absent in the prokaryotic counterparts. Among the DEKA residues, Lys is of the most importance since its mutation to Arg abolishes the Na+/K+ selectivity. In this work, we modeled the pore domain of mammalian Nav channels by mutating the four residues at the constriction site of a prokaryotic Nav channel (NavRh to DEKA, and then mechanistically investigated the contribution of Lys in cation selection using molecular dynamics simulations. The DERA mutant was generated as a comparison to understand the loss of ion selectivity caused by the K-to-R mutation. Simulations and free energy calculations on the mutants indicate that Lys facilitates Na+/K+ selection by electrostatically repelling the cation to a highly Na+-selective location sandwiched by the carboxylate groups of Asp and Glu at the constriction site. In contrast, the electrostatic repulsion is substantially weakened when Lys is mutated to Arg, because of two intrinsic properties of the Arg side chain: the planar geometric design and the sparse charge distribution of the guanidine group.

Loss of metal ions, disulfide reduction and mutations related to familial ALS promote formation of amyloid-like aggregates from superoxide dismutase.

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Zeynep A Oztug Durer

Full Text Available Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1 are one of the causes of familial amyotrophic lateral sclerosis (FALS. Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1 formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

Protein profiles of hatchery egg shell membrane.

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Rath, N C; Liyanage, R; Makkar, S K; Lay, J O

2016-01-01

Eggshells which consist largely of calcareous outer shell and shell membranes, constitute a significant part of poultry hatchery waste. The shell membranes (ESM) not only contain proteins that originate from egg whites but also from the developing embryos and different contaminants of microbial and environmental origins. As feed supplements, during post hatch growth, the hatchery egg shell membranes (HESM) have shown potential for imparting resistance of chickens to endotoxin stress and exert positive health effects. Considering that these effects are mediated by the bioactive proteins and peptides present in the membrane, the objective of the study was to identify the protein profiles of hatchery eggshell membranes (HESM). Hatchery egg shell membranes were extracted with acidified methanol and a guanidine hydrochloride buffer then subjected to reduction/alkylation, and trypsin digestion. The methanol extract was additionally analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). The tryptic digests were analyzed by liquid chromatography and tandem mass spectrometry (LC-MS-MS) to identify the proteins. Our results showed the presence of several proteins that are inherent and abundant in egg white such as, ovalbumin, ovotransferrin, ovocleidin-116, and lysozyme, and several proteins associated with cytoskeletal, cell signaling, antimicrobial, and catalytic functions involving carbohydrate, nucleic acid, and protein metabolisms. There were some blood derived proteins most likely originating from the embryos and several other proteins identified with different aerobic, anaerobic, gram positive, gram negative, soil, and marine bacterial species some commensals and others zoonotic. The variety of bioactive proteins, particularly the cell signaling and enzymatic proteins along with the diverse microbial proteins, make the HESM suitable for nutritional and biological application to improve post hatch immunity of poultry.

Evaluation and optimization of DNA extraction and purification procedures for soil and sediment samples.

Science.gov (United States)

Miller, D N; Bryant, J E; Madsen, E L; Ghiorse, W C

1999-11-01

We compared and statistically evaluated the effectiveness of nine DNA extraction procedures by using frozen and dried samples of two silt loam soils and a silt loam wetland sediment with different organic matter contents. The effects of different chemical extractants (sodium dodecyl sulfate [SDS], chloroform, phenol, Chelex 100, and guanadinium isothiocyanate), different physical disruption methods (bead mill homogenization and freeze-thaw lysis), and lysozyme digestion were evaluated based on the yield and molecular size of the recovered DNA. Pairwise comparisons of the nine extraction procedures revealed that bead mill homogenization with SDS combined with either chloroform or phenol optimized both the amount of DNA extracted and the molecular size of the DNA (maximum size, 16 to 20 kb). Neither lysozyme digestion before SDS treatment nor guanidine isothiocyanate treatment nor addition of Chelex 100 resin improved the DNA yields. Bead mill homogenization in a lysis mixture containing chloroform, SDS, NaCl, and phosphate-Tris buffer (pH 8) was found to be the best physical lysis technique when DNA yield and cell lysis efficiency were used as criteria. The bead mill homogenization conditions were also optimized for speed and duration with two different homogenizers. Recovery of high-molecular-weight DNA was greatest when we used lower speeds and shorter times (30 to 120 s). We evaluated four different DNA purification methods (silica-based DNA binding, agarose gel electrophoresis, ammonium acetate precipitation, and Sephadex G-200 gel filtration) for DNA recovery and removal of PCR inhibitors from crude extracts. Sephadex G-200 spin column purification was found to be the best method for removing PCR-inhibiting substances while minimizing DNA loss during purification. Our results indicate that for these types of samples, optimum DNA recovery requires brief, low-speed bead mill homogenization in the presence of a phosphate-buffered SDS-chloroform mixture, followed

Covalent DNA-protein crosslinking occurs after hyperthermia and radiation

International Nuclear Information System (INIS)

Cress, A.E.; Bowden, G.T.

1983-01-01

Covalent DNA-protein crosslinks occur in exponentially growing mouse leukemia cells (L1210) after exposure to ionizing radiation. The amount of DNA-protein crosslinks as measured by a filter binding assay is dose dependent upon X irradiation. Although hyperthermia and radiation in combination are synergistic with respect to cell lethality, the combination does not result in an increase of DNA-protein crosslinks when assayed immediately following treatments. Hyperthermia (43 degrees C/15 min) given prior to radiation does not alter the radiation dose dependency of the amount of initial crosslinking. In addition, the amount of DNA-protein crosslinking produced by heat plus radiation is independent of the length of heating the cells at 43 degrees C. The DNA-protein crosslinks produced by 50-Gy X ray alone are removed after 2 hr at 37 degrees C. However, if hyperthermia (43 degrees C/15 min) is given prior to 100-Gy X ray, the removal of DNA-protein crosslinks is delayed until 4.0 hr after radiation. Phospho-serine and phospho-threonine bonds are not produced with either radiation or the combination of hyperthermia plus radiation as judged by the resistance of the bonds to guanidine hydrochloride. However, hyperthermia plus radiation causes an increase in phosphate to nitrogen type bonding. These results show that radiation alone causes covalent DNA-protein crosslinks. Hyperthermia in combination with radiation does not increase the total amount of the crosslinks but delays the removal of the crosslinks and alters the distribution of the types of chemical bonding. These data suggest that the synergistic action on hyperthermia with radiation is more related to the rate of removal and the type of chemical bonding involved in the covalent DNA-protein crosslinks rather than the amount of DNA-protein crosslinks

Antigenic characterization of an abnormal isoform of prion protein using a new diverse panel of monoclonal antibodies

International Nuclear Information System (INIS)

Kim, Chan-Lan; Umetani, Atsushi; Matsui, Toshio; Ishiguro, Naotaka; Shinagawa, Morikazu; Horiuchi, Motohiro

2004-01-01

We established a panel of monoclonal antibodies (mAbs) against prion protein (PrP) by immunizing PrP gene-ablated mice with the pathogenic isoform of prion protein (PrP Sc ) or recombinant prion protein (rPrP). The mAbs could be divided into at least 10 groups by fine epitope analyses using mutant rPrPs and pepspot analysis. Seven linear epitopes, lying within residues 56-90, 119-127, 137-143, 143-149, 147-151, 163-169, and 219-229, were defined by seven groups of mAbs, although the remaining three groups of mAbs recognized discontinuous epitopes. We attempted to examine whether any of these epitopes are located on the accessible surface of PrP Sc . However, no mAbs reacted with protease-treated PrP Sc purified from scrapie-affected mice, even when PrP Sc was dispersed into a detergent-lipid protein complex, to reduce the size of PrP Sc aggregates. In contrast, denaturation of PrP Sc by guanidine hydrochloride efficiently exposed all of the epitopes. This suggests that any epitope recognized by this panel of mAbs is buried within the PrP Sc aggregates. Alternatively, if the corresponding region(s) are on the surface of PrP Sc , the region(s) may be folded into conformations to which the mAbs cannot bind. The reactivity of a panel of mAb also showed that the state of PrP Sc aggregation influenced the denaturation process, and the sensitivity to denaturation appeared to vary between epitopes. Our results demonstrate that this new panel of well-characterized mAbs will be valuable for studying the biochemistry and biophysics of PrP molecules as well as for the immuno-diagnosis of prion diseases

Types of household humidifier disinfectant and associated risk of lung injury (HDLI) in South Korea.

Science.gov (United States)

Park, Dong-Uk; Ryu, Seung-Hun; Lim, Heung-Kyu; Kim, Sun-Kyung; Choi, Ye-Yong; Ahn, Jong-Ju; Lee, Eun; Hong, Sang-Bum; Do, Kyung-Hyun; Cho, Jae-Lim; Bae, Mun-Joo; Shin, Dong-Chun; Paek, Do-Myung; Hong, Soo-Jong

2017-10-15

From 2002 through 2015, hundreds of people died of fatal lung injuries associated with the use of humidifier disinfectants (HDs) in Korea. Several chemical disinfectants used for household humidifiers were later clinically confirmed to cause HD-associated lung injury (HDLI). The aim of this study is to evaluate the registered lung disease cases and to compare the distribution of HDLI patients, including deaths, by HD use characteristics including types of HD and HD brands categorized by age group. A total of 530 registered were clinically examined through two rounds of investigations conducted from July 2013 until April 2015. Information on HD use was obtained from a structured questionnaire and home investigations. Approximately one-half of the patients (n=221) were clinically confirmed to be associated with the use of HDs. Pregnant women (n=35, 16%) and pre-school children≤6years old (n=128, 58%) accounted for most of the HD-associated lung injury patients (n=163, 74%). Sixty-seven percent of HDLI patients developed HDLI after less than one year of HD use. HD products containing polyhexamethylene guanidine phosphate (PHMG) were the most frequently used among confirmed HDLI patients (n=123, 55.7%), followed by oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH) (n=24, 10.9%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (n=3, 1.4%). Other HDs did not appear to be linked to HDLI. The majority of the HDLI patients (n=85, 38.5%) was found to use only Oxy Saksak® products containing PHMG. The development of HDLI was clinically found to be associated with the use of several HD products containing PHMG and PGH, and to lesser extent, CMIT/MIT. Copyright © 2017 Elsevier B.V. All rights reserved.

Lung fibroblasts may play an important role in clearing apoptotic bodies of bronchial epithelial cells generated by exposure to PHMG-P-containing solution.

Science.gov (United States)

Park, Eun-Jung; Park, Sung-Jin; Kim, Sanghwa; Lee, Kyuhong; Chang, Jaerak

2018-04-01

Polyhexamethylene guanidine (PHMG) has been widely used in the industry owing to its excellent biocidal, anti-corrosive, and anti-biofouling properties. In Korea, consumers exposed to PHMG-phosphate (PHMG-P)-containing humidifier disinfectant have begun to suffer from fibrotic lung injury-related symptoms for unknown reasons. However, no appropriate treatment has yet been found because the detail toxic mechanism has not been identified. Herein, we first studied the toxic mechanism of PHMG-P-containing solution using human normal bronchial epithelial cells (BEAS-2B cells). When exposed for 24 h, PHMG-P-containing solution rapidly decreased cell viability from around 6 h after exposure and significantly increased of the phosphatidylserine exposure and the LDH release. At 6 h of exposure, the material contained in the solution was found to be bound to the cell membrane and the inner wall of vacuoles, and damaged the cell membrane and organelles. In addition, a significant increase of IFN-γ was observed among cytokines, the expression of apoptosis-, autophagy-, and membrane and DNA damage-related proteins was also enhanced. Meanwhile, the level of intracellular ROS and the secretion of IL-8 and CXCL-1, which are chemokines for professional phagocytes, decreased. Thus, we treated dead BEAS-2B cells to lung fibroblasts (HFL-1), non-professional phagocytes, and then we observed that the dead cells rapidly attached to HFL-1 cells and were taken up. Additionally, increased secretion of IL-8 and CXCL-1 was observed in the cells. Based on these results, we suggest that pulmonary exposure to PHMG-P induces apoptosis of bronchial epithelial cells and lung fibroblasts might play an important role in the clearance of the apoptotic debris. Copyright © 2018 Elsevier B.V. All rights reserved.

Acute cholestatic liver injury caused by polyhexamethyleneguanidine hydrochloride admixed to ethyl alcohol.

Science.gov (United States)

Ostapenko, Y N; Brusin, K M; Zobnin, Y V; Shchupak, A Y; Vishnevetskiy, M K; Sentsov, V G; Novikova, O V; Alekseenko, S A; Lebed'ko, O A; Puchkov, Y B

2011-07-01

Polyhexamethyleneguanidine hydrochloride (PHMG) is an antimicrobial biocide of the guanidine family. In the period from August 2006 to May 2007, more than 12500 patients were admitted to hospital with a history of drinking illegal cheap "vodka" in 44 different regions in Russia, of whom 9.4% died. In reality, the "vodka" was an antiseptic liquid composed of ethanol (≈93%), diethyl phthalate, and 0.1-0.14% PHMG (brand name "Extrasept-1"). We performed an analysis of the clinical features and outcome in four poisoning treatment centers in the cities of Perm, Ekaterinburg, Irkutsk, and Khabarovsk. A total of 579 patients (215 females and 364 males) with similar symptoms were included. The main symptoms on admission included jaundice (99.7%), skin itch (78.4%), weakness (96%), anorexia (65.8%), dizziness (65.3%), nausea (54.8%), vomiting (22.6%), stomach ache (52.7%), diarrhea (32%), and fever (50%). Mild symptoms were found in 2.5% of cases, moderate in 63%, and severe in 34.5%. Laboratory results were (mean ± SD): total bilirubin 249 ± 158 μmol/L, direct bilirubin 166 ± 97 μmol/L, cholesterol 14 ± 8 mmol/L, alanine aminotransferase 207 ± 174 IU/L, aspartate aminotransferase 174 ± 230 IU/L, alkaline phosphatase 742 ± 751 IU/L, and gamma-glutamyltranspeptidase 1199 ± 1095 IU/L. Patients generally recovered over a period of 1-5 months, although high levels of alkaline phosphatase and gamma-glutamyltranspeptidase were still found in all patients examined after 6 months. Sixty-one patients (10.5%) died between 23 and 150 days after poisoning. Local cholestasis, inflammatory infiltration, and fibrosis developing into cirrhosis were found by liver biopsy. Acute liver injury caused by PHMG-hydrochloride or PHMG in combination with either ethanol or diethyl phthalate can be characterized as cholestatic hepatitis with a severe inflammatory component causing high mortality.

Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro

Science.gov (United States)

Kaushal, Nidhi; Robson, Matthew J.; Rosen, Abagail; McCurdy, Christopher R.; Matsumoto, Rae R.

2014-01-01

Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3,-8 and-9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 °C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 °C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 °C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

Bradykinin-induced lung inflammation and bronchoconstriction: role in parainfluenze-3 virus-induced inflammation and airway hyperreactivity.

Science.gov (United States)

Broadley, Kenneth J; Blair, Alan E; Kidd, Emma J; Bugert, Joachim J; Ford, William R

2010-12-01

Inhaled bradykinin causes bronchoconstriction in asthmatic subjects but not nonasthmatics. To date, animal studies with inhaled bradykinin have been performed only in anesthetized guinea pigs and rats, where it causes bronchoconstriction through sensory nerve pathways. In the present study, airway function was recorded in conscious guinea pigs by whole-body plethysmography. Inhaled bradykinin (1 mM, 20 s) caused bronchoconstriction and influx of inflammatory cells to the lungs, but only when the enzymatic breakdown of bradykinin by angiotensin-converting enzyme and neutral endopeptidase was inhibited by captopril (1 mg/kg i.p.) and phosphoramidon (10 mM, 20-min inhalation), respectively. The bronchoconstriction and cell influx were antagonized by the B(2) kinin receptor antagonist 4-(S)-amino-5-(4-{4-[2,4-dichloro-3-(2,4-dimethyl-8-quinolyloxymethyl)phenylsulfonamido]-tetrahydro-2H-4-pyranylcarbonyl}piperazino)-5-oxopentyl](trimethyl)ammonium chloride hydrochloride (MEN16132) when given by inhalation (1 and 10 μM, 20 min) and are therefore mediated via B(2) kinin receptors. However, neither intraperitioneal MEN16132 nor the peptide B(2) antagonist icatibant, by inhalation, antagonized these bradykinin responses. Sensitization of guinea pigs with ovalbumin was not sufficient to induce airway hyperreactivity (AHR) to the bronchoconstriction by inhaled bradykinin. However, ovalbumin challenge of sensitized guinea pigs caused AHR to bradykinin and histamine. Infection of guinea pigs by nasal instillation of parainfluenza-3 virus produced AHR to inhaled histamine and lung influx of inflammatory cells. These responses were attenuated by the bradykinin B(2) receptor antagonist MEN16132 and H-(4-chloro)DPhe-2'(1-naphthylalanine)-(3-aminopropyl)guanidine (VA999024), an inhibitor of tissue kallikrein, the enzyme responsible for lung synthesis of bradykinin. These results suggest that bradykinin is involved in virus-induced inflammatory cell influx and AHR.

Extractive liquid-liquid spectrophotometric procedure for the determination of thiocyanate ions employing the ion pair reagent amiloride monohydrochloride

International Nuclear Information System (INIS)

Bashammakh, A.S.; Bahaffi, S.O.; Al-Sibaai, A.A.; Al-Wael, H.O.; El-Shahawi, M.S.

2007-01-01

An accurate, inexpensive and less laborious liquid-liquid extractive spectrophotometric procedure for the determination of thiocyanate ions in aqueous media has been developed. The method has been based upon the formation of a yellow colored complex ion associate of the ion-pairing reagent 1-(3, 5-diamino-6-chloropyrazinecarboxyl) guanidine hydrochloride monohydrate, namely amiloride hydrochloride, DPG + .Cl - and the thiocyanate ions in aqueous media containing HNO 3 (0.5 mol L -1 ) and subsequent extraction with 4-methyl-2-pentanone. The absorption electronic spectrum of the ion associate showed one well-defined peak at λ max 366 nm. The stoichiometric mole ratio of DPG + .Cl - to the thiocyanate ions is 1:1.The effective molar absorptivity (ε) of the ion associate at λ max 366 nm is 1.1 ± 0.1 x 10 4 L mol -1 cm -1 . The extraction constants (K d , K ex , and β) enabled a simple and convenient use of the developed binary ion associate for the extractive spectrophotometric determination of traces of thiocyanate ions in the aqueous media. Beer's law and Ringbom's plots are obeyed in the concentration range 0.05-10 and 0.1-7 μg mL -1 of the thiocyanate ions, respectively with a relative standard deviation of ±2.3%. The calculated lower limits of detection (LOD) and quantitation (LOQ) of the developed procedure for the thiocyanate ions were found equal to 0.02 and 0.066 μg mL -1 , respectively. The developed method has been applied for the determination of trace amounts of thicyanate ions in tap-, waste- and natural water samples and compared successfully with the reported methods at the 95% confidence level. The proposed method was also applied successfully for the determination of thiocyanate ions in saliva samples

[Effects of redox state of disulfide bonds on the intrinsic fluorescence and denaturation of Trx-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea].

Science.gov (United States)

Zhang, Teng; Feng, Juan; Li, Yang; Chen, Rui; Tang, Li-Xia; Pang, Xiao-Feng; Ren, Zheng-Long

2010-02-01

In the present paper, thioredoxin-fused gibberellin-induced cysteine-rich protein from Gymnadnia conopsea, desigated as Trx-GcGASA and expressed prokaryotically, was purified and identified by using Ni(2+) -NTA affinity chromatography column and SDS-PAGE, and then its intrinsic fluorescence was investigated in the absence and presence of dithiothreitol (DTT), oxidized glutathione (GSSG), peroxide and guanidine hydrochloride (GdnHCl) by means of steady-state fluorescence spectroscopic methods. It was found that (1) at the neutral pH Trx-GcGASA had maximum fluorescence emission at 305 nm following excitation at different wavelengths varying from 250 to 280 nm, which was ascribed to the fluorescence emission from tyrosine residues. (2) The reduction of disulphide bonds lead to the changes in the relative fluorescence intensity between tyrosine and tryptophan residues from 0.7 to 1.8. (3) Both Tyr and Trp residues underwent 12%-21% decrease in fluorescence intensity with the addition of 0.5 mmol x L(-1) GSSG or 5 mmol x L(-1) peroxide. The latter was roughly consistent with the antioxidative activity reported in vivo. (4) No matter whether 1 mmol x L(-1) DTT was absent or present, the fusion protein could not be fully unfolded with lambda(max) Trx-GcGASA experienced GdnHCl-induced denaturation process, and the unfolding equilibrium curve could be well fitted by using two-state model, giving the Gibbs free energy change (deltaG) of 3.7 kJ x mol(-1). However, it was not the case for reduced Trx-GcGASA protein. The aforementioned experimental results will not only provide some guides to investigate the effects of fusion partner Trx on the unfolding thermodynamics, kinetics and refolding process of Trx-GcGASA, but also will be useful for further studies on the strucuture of GA-induced cysteine-rich protein with the help of spectroscopic methods.

Nitric oxide and chronic colitis

Directory of Open Access Journals (Sweden)

Matthew B Grisham

1996-01-01

Full Text Available Nitric oxide (NO is thought to play an important role in modulating the inflammatory response by virtue of its ability to affect bloodflow, leukocyte function and cell viability. The objective of this study was to assess the role that NO may play in mediating the mucosal injury and inflammation in a model of chronic granulomatous colitis using two pharmacologically different inhibitors of nitric oxide synthase (NOS. Chronic granulomatous colitis with liver and spleen inflammation was induced in female Lewis rats via the subserosal (intramural injection of peptidoglycan/polysaccharide (PG/PS derived from group A streptococci. Chronic NOS inhibition by oral administration of NG-nitro-L-arginine methyl ester (L-NAME (15 µmol/kg/day or amino-guanidine (AG (15 µmol/ kg/day was found to attenuate the PG/PS-induced increases in macroscopic colonic inflammation scores and colonic myeloperoxidase activity. Only AG -- not L-NAME – attenuated the PG/PS-induced increases in colon dry weight. Both L-NAME and AG significantly attenuated the PG/PS-induced increases in spleen weight whereas neither was effective at significantly attenuating the PG/PS-induced increases in liver weight. Although both L-NAME and AG inhibited NO production in vivo, as measured by decreases in plasma nitrite and nitrate levels, only AG produced significantly lower values (38±3 versus 83±8 µM, respectively, P<0.05. Finally, L-NAME, but not AG, administration significantly increased mean arterial pressure from 83 mmHg in colitic animals to 105 mmHg in the PG/PS+ L-NAME-treated animals (P<0.05. It is concluded that NO may play an important role in mediating some of the pathophysiology associated with this model of chronic granulomatous colitis.

Amplification of a transcriptionally active DNA sequence in the human brain

International Nuclear Information System (INIS)

Yakovlev, A.G.; Sazonov, A.E.; Spunde, A.Ya.; Gindilis, V.M.

1986-01-01

The authors present their findings of tissue-specific amplification of a DNA fragment actively transcribed in the human brain. This genome fragment was found in the library complement of cDNA of the human brain and evidently belongs to a new class of moderate repetitions of DNA with an unstable copying capacity in the human genome. The authors isolated total cell RNA from various human tissues (brain, placenta), and rat tissues (brain, liver), by the method of hot phenol extraction with guanidine thiocynate. The poly(A + ) RNA fraction was isolated by chromatography. Synthesis of cDNA was done on a matrix of poly(A + ) RNA of human brain. The cDNA obtained was cloned in plasmid pBR322 for the PstI site using (dC/dG) sequences synthesized on the 3' ends of the vector molecule and cDNA respectively. In cloning 75 ng cDNA, the authors obtained approximately 10 5 recombinant. This library was analyzed by the hybridization method on columns with two radioactive ( 32 P) probes: the total cDNA preparation and the total nuclear DNA from the human brain. The number of copies of the cloned DNA fragment in the genome was determined by dot hybridization. Restricting fragments of human and rat DNA genomes homologous to the cloned cDNA were identified on radio-autographs. In each case, 10 micrograms of EcoRI DNA hydrolyzate was fractionated in 1% agarose gel. The probe was also readied with RNA samples fractionated in agarose gel with formaldehyde and transferred to a nitrocellulose filter under weak vacuum. The filter was hybridized with 0.1 micrograms DNA pAG 02, labeled with ( 32 P) to a specific activity of 0.5-1 x 10 9 counts/min x microgram. The autograph was exposed with amplifying screens at -70 0 C for 2 days

Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

Energy Technology Data Exchange (ETDEWEB)

Arnold, John [Univ. of California, Berkeley, CA (United States)

2015-01-21

The uranyl cation (UO₂²⁺) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

Identification of D3 and sigma receptors in the rat striatum and nucleus accumbens using (+/-)-7-hydroxy-N,N-di-n-[3H]propyl-2-aminotetralin and carbetapentane.

Science.gov (United States)

Wallace, D R; Booze, R M

1995-02-01

Cross-reactions between dopamine D3 and sigma receptor ligands were investigated using (+/-)-7-hydroxy-N,N-di-n-[3H]propyl-2-aminotetralin [(+/-)-7-OH-[3H]-DPAT], a putative D3-selective radioligand, in conjunction with the unlabeled sigma ligands 1,3-di(2-tolyl)guanidine (DTG), carbetapentane, and R(-)-N-(3-phenyl-1-propyl)-1-phenyl-2-aminopropane [R(-)-PPAP]. In transfected CCL1.3 mouse fibroblasts expressing the human D3 receptor, neither DTG nor carbetapentane (0.1 microM) displaced (+/-)-7-OH-[3H]DPAT binding. R(-)-PPAP (0.1 microM) displaced 39.6 +/- 1.0% of total (+/-)-7-OH-[3H]DPAT binding. In striatal and nucleus accumbens homogenates, (+/-)-7-OH-[3H]DPAT labeled a single site (15-20 fmol/mg of protein) with high (1 nM) affinity. Competition analysis with carbetapentane defined both high- and low-affinity sites in striatal (35 and 65%, respectively) and nucleus accumbens (59 and 41%, respectively) tissue, yet R(-)-PPAP identified two sites in equal proportion. Carbetapentane and R(-)-PPAP (0.1 microM) displaced approximately 20-50% of total (+/-)-7-OH-[3H]DPAT binding in striatum, nucleus accumbens, and olfactory tubercle in autoradiographic studies, with the nucleus accumbens shell subregion exhibiting the greatest displacement. To determine directly (+)-7-OH-[3H]DPAT binding to sigma receptors, saturation analysis was performed in the cerebellum while masking D3 receptors with 1 microM dopamine. Under these conditions (+)-7-OH-[3H]DPAT labeled sigma receptors with an affinity of 24 nM. These results suggest that (a) (+/-)-7-OH-[3H]DPAT binds D3 receptors with high affinity in rat brain and (b) a significant proportion of (+/-)-7-OH-[3H]DPAT binding consists of sigma 1 sites and the percentages of these sites differ among the subregions of the striatum and nucleus accumbens.

Specific targeting for the treatment of neuroendocrine tumors

International Nuclear Information System (INIS)

Hoefnagel, C.A.

2003-01-01

For the treatment of neuroendocrine tumors three ways of specific targeting of radionuclides prevail: by 131 I-meta-iodo-benzyl-guanidine (MIBG), which is taken up by an active uptake-1 mechanism and stored in neurosecretory granules of neural crest tumor cells, by radiolabeled peptides, in particular the somatostatin analogs octreotide and lanreotide, targeting the peptide receptors, and by radiolabeled antibodies, which target tumor cell surface antigens. The choice depends on the indication, the results of diagnostic imaging using tracer amounts of these agents, the availability and feasibility of radionuclide therapy and of other treatment modalities. The applications, clinical results and developments for the major indications are reviewed. 131 I-MIBG therapy has a cumulative response rate of 50%, associated with little toxicity, in metastatic pheochromocytoma, paraganglioma and neuroblastoma, whereas its role is primarily palliative in patients with medullary thyroid carcinoma and carcinoid tumors. Treatment using 90 Y- or 177 Lu-labeled octreotide/lanreotide is mostly used in neuroendocrine gastro-entero-pancreatic (GEP) tumors and paraganglioma, attaining stabilization of disease anti-palliation in the majority of patients. As this treatment is specific for the receptor rather than for the tumor type, it may also be applicable to other, non-neuroendocrine tumors. Radioimmunotherapy is applied in medullary thyroid carcinoma, in which a phase I/II study using bi-specific anti-DTPA/anti-CEA immuno-conjugates followed by 131 I-hapten has proven some degree of success, and may be used in neuroblastoma more effectively than before, once chimeric and humanized monoclonal antibodies become available for therapy. Integration of these specific and noninvasive therapies at an optimal moment into the treatment protocols of these diseases may enhance their effectiveness and acceptance. (author)

Specific targeting for the treatment of neuroendocrine tumors; Ciblage specifique pour le traitement des tumeurs neuro-endocrines

Energy Technology Data Exchange (ETDEWEB)

Hoefnagel, C.A. [Netherlands Cancer Institute 1066 CX Amsterdam, Dept. of Nuclear Medicine (Netherlands)

2003-09-01

For the treatment of neuroendocrine tumors three ways of specific targeting of radionuclides prevail: by {sup 131}I-meta-iodo-benzyl-guanidine (MIBG), which is taken up by an active uptake-1 mechanism and stored in neurosecretory granules of neural crest tumor cells, by radiolabeled peptides, in particular the somatostatin analogs octreotide and lanreotide, targeting the peptide receptors, and by radiolabeled antibodies, which target tumor cell surface antigens. The choice depends on the indication, the results of diagnostic imaging using tracer amounts of these agents, the availability and feasibility of radionuclide therapy and of other treatment modalities. The applications, clinical results and developments for the major indications are reviewed. {sup 131}I-MIBG therapy has a cumulative response rate of 50%, associated with little toxicity, in metastatic pheochromocytoma, paraganglioma and neuroblastoma, whereas its role is primarily palliative in patients with medullary thyroid carcinoma and carcinoid tumors. Treatment using {sup 90}Y- or {sup 177}Lu-labeled octreotide/lanreotide is mostly used in neuroendocrine gastro-entero-pancreatic (GEP) tumors and paraganglioma, attaining stabilization of disease anti-palliation in the majority of patients. As this treatment is specific for the receptor rather than for the tumor type, it may also be applicable to other, non-neuroendocrine tumors. Radioimmunotherapy is applied in medullary thyroid carcinoma, in which a phase I/II study using bi-specific anti-DTPA/anti-CEA immuno-conjugates followed by {sup 131}I-hapten has proven some degree of success, and may be used in neuroblastoma more effectively than before, once chimeric and humanized monoclonal antibodies become available for therapy. Integration of these specific and noninvasive therapies at an optimal moment into the treatment protocols of these diseases may enhance their effectiveness and acceptance. (author)

Single Molecular Level Probing of Structure and Dynamics of Papain Under Denaturation.

Science.gov (United States)

Sengupta, Bhaswati; Chaudhury, Apala; Das, Nilimesh; Sen, Pratik

2017-01-01

Papain is a cysteine protease enzyme present in papaya and known to help in digesting peptide. Thus the structure and function of the active site of papain is of interest. The objective of present study is to unveil the overall structural transformation and the local structural change around the active site of papain as a function of chemical denaturant. Papain has been tagged at Cys-25 with a thiol specific fluorescence probe N-(7- dimethylamino-4-methylcoumarin-3-yl) iodoacetamide (DACIA). Guanidine hydrochloride (GnHCl) has been used as the chemical denaturant. Steady state, time-resolved, and single molecular level fluorescence techniques was applied to map the change in the local environment. It is found that papain undergoes a two-step denaturation in the presence of GnHCl. Fluorescence correlation spectroscopic (FCS) data indicate that the size (hydrodynamic diameter) of native papain is ~36.8 Å, which steadily increases to ~53 Å in the presence of 6M GnHCl. FCS study also reveals that the conformational fluctuation time of papain is 6.3 µs in its native state, which decreased to 2.7 µs in the presence of 0.75 M GnHCl. Upon further increase in GnHCl concentration the conformational fluctuation time increase monotonically till 6 M GnHCl, where the time constant is measured as 14 µs. On the other hand, the measurement of ellipticity, hence the helical structure, by circular dichroism spectroscopy is found to be incapable to capture such structural transformation. It is concluded that in the presence of small amount of GnHCl the active site of papain takes up a more compact structure (although the overall size increases) than in the native state, which has been designated as the intermediate state. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Radiation Synthesis of Some Copolymers and their Potential Industrial Applications

International Nuclear Information System (INIS)

Hegazy, N.R.

2015-01-01

The field of biomaterials has advanced rapidly in the recent years. Much attention has been focused on the research and developments of polymer for biomedical applications. One of the most promising classes of materials for biomedical applications seems to be the hydrogels. In this connection, the first part concern with preparation of various types of hydrogels by using gamma irradiation for possible Industrial uses. Novel super absorbent hydrogels were prepared successfully from carboxymethylcellulose sodium (CMC) and acrylamide (AAm) due to their good biocompatibility. The structure of the hydrogels was characterized by FT-IR and thermogravimetric analysis. Scanning electron microscopy was also carried out to study the surface morphology of the hydrogel and it verifies that the synthesized hydrogels have a porous structure then the synthesis of silver (AAm/CMC) nano composite hydrogel from the prepared (AAm/CMC) hydrogel has done and characterized using UV-visible, XRD, EDX, SEM and TEM which confirmed the formation of silver nanoparticles and determined its particle size. Their equilibrium swelling ratio in distilled water and different physiological fluids were evaluated. Moreover, the hydrogels exhibited smart swelling and shrinking in different aqueous solutions that could be controlled by changing CMC content. The second part concern with the synthesis of grafting polymers using γ-rays and the factors affect on the grafting process onto LDPE, HDPE and PP films by binary comonomer GMA:NVIm such as solvent, concentration, composition and dose were investigated. The grafted films were characterized by enough number of techniques. Afterwards, the grafted films were treated by many chemical reagents such as Isonicotinamide, 4(6) Aminouracil, Sulpha methoxy di azine and Guanidine hydrochloride at different interval times, respectively. The prepared hydrogels are promising for the applications in the biomaterials area and the applicability of grafted films to be

Molecular recognition of nucleotides in micelles and the development and expansion of a chemistry outreach program

Science.gov (United States)

Schechinger, Linda Sue

I. To investigate the delivery of nucleotide-based drugs, we are studying molecular recognition of nucleotide derivatives in environments that are similar to cell membranes. The Nowick group previously discovered that membrane-like surfactant micelles tetradecyltrimethylammonium bromide (TTAB) micelle facilitate molecular of adenosine monophosphate (AMP) recognition. The micelles bind nucleotides by means of electrostatic interactions and hydrogen bonding. We observed binding by following 1H NMR chemical shift changes of unique hexylthymine protons upon addition of AMP. Cationic micelles are required for binding. In surfactant-free or sodium dodecylsulfate solutions, no hydrogen bonding is observed. These observations suggest that the cationic surfactant headgroups bind the nucleotide phosphate group, while the intramicellar base binds the nucleotide base. The micellar system was optimized to enhance binding and selectivity for adenosine nucleotides. The selectivity for adenosine and the number of phosphate groups attached to the adenosine were both investigated. Addition of cytidine, guanidine, or uridine monophosphates, results in no significant downfield shifting of the NH resonance. Selectivity for the phosphate is limited, since adenosine mono-, di-, and triphosphates all have similar binding constants. We successfully achieved molecular recognition of adenosine nucleotides in micellar environments. There is significant difference in the binding interactions between the adenosine nucleotides and three other natural nucleotides. II. The UCI Chemistry Outreach Program (UCICOP) addresses the declining interest of the nations youth for science. UCICOP brings fun and exciting chemistry experiments to local high schools, to remind students that science is fun and has many practical uses. Volunteer students and alumni of UCI perform the demonstrations using scripts and material provided by UCICOP. The preparation of scripts and materials is done by two coordinators

Single Stage Contactor Testing Of The Next Generation Solvent Blend

Energy Technology Data Exchange (ETDEWEB)

Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

2014-01-06

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

Purification of CD47-streptavidin fusion protein from bacterial lysate using biotin-agarose affinity chromatography.

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Salehi, Nasrin; Peng, Ching-An

2016-07-08

CD47 is a widely expressed transmembrane glycoprotein that modulates the activity of a plethora of immune cells via its extracellular domain. Therefore, CD47 plays important roles in the regulation of immune responses and may serve as targets for the development of immunotherapeutic agents. To make sure CD47 functionality is intact under the process of protein conjugation, CD47-streptavidin fusion protein was expressed and purified because it can easily bind to biotin-tagged materials via the unique biotin-streptavidin affinity. In this study, gene sequences of CD47 extracellular domain (CD47ECD) and core streptavidin (coreSA) with a total 834 bp were inserted into pET20b plasmid to construct recombinant plasmid encoding CD47-SA fusion gene. After bacteria transformation, the CD47-SA fusion protein was expressed by isopropyl-β-d-thiogalactopyranoside (IPTG) induction. The collected bacteria lysate was loaded on biotinylated agarose to proceed the purification of CD47-SA fusion protein. Due to the unexpected high affinity between biotin and coreSA, standard washing and elution approaches (e.g., varying pH, using biotin, and applying guanidine hydrochloride) reported for biotin-streptavidin affinity chromatography were not able to separate the target fusion protein. Instead, using low concentration of the non-ionic detergent Triton X-100 followed with alkaline buffer could efficiently weaken the binding between biotin and coreSA, thereby eluting out CD47-SA fusion protein from the biotin agarose column. The purified CD47-SA fusion protein was further characterized by molecular biology methods and its antiphagocytic functionality was confirmed by the phagocytosis assay. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:949-958, 2016. © 2016 American Institute of Chemical Engineers.

Lysine and the Na+/K+ Selectivity in Mammalian Voltage-Gated Sodium Channels.

Science.gov (United States)

Li, Yang; Liu, Huihui; Xia, Mengdie; Gong, Haipeng

2016-01-01

Voltage-gated sodium (Nav) channels are critical in the generation and transmission of neuronal signals in mammals. The crystal structures of several prokaryotic Nav channels determined in recent years inspire the mechanistic studies on their selection upon the permeable cations (especially between Na+ and K+ ions), a property that is proposed to be mainly determined by residues in the selectivity filter. However, the mechanism of cation selection in mammalian Nav channels lacks direct explanation at atomic level due to the difference in amino acid sequences between mammalian and prokaryotic Nav homologues, especially at the constriction site where the DEKA motif has been identified to determine the Na+/K+ selectivity in mammalian Nav channels but is completely absent in the prokaryotic counterparts. Among the DEKA residues, Lys is of the most importance since its mutation to Arg abolishes the Na+/K+ selectivity. In this work, we modeled the pore domain of mammalian Nav channels by mutating the four residues at the constriction site of a prokaryotic Nav channel (NavRh) to DEKA, and then mechanistically investigated the contribution of Lys in cation selection using molecular dynamics simulations. The DERA mutant was generated as a comparison to understand the loss of ion selectivity caused by the K-to-R mutation. Simulations and free energy calculations on the mutants indicate that Lys facilitates Na+/K+ selection by electrostatically repelling the cation to a highly Na+-selective location sandwiched by the carboxylate groups of Asp and Glu at the constriction site. In contrast, the electrostatic repulsion is substantially weakened when Lys is mutated to Arg, because of two intrinsic properties of the Arg side chain: the planar geometric design and the sparse charge distribution of the guanidine group.

Apigenin has anti-atrophic gastritis and anti-gastric cancer progression effects in Helicobacter pylori-infected Mongolian gerbils.

Science.gov (United States)

Kuo, Chao-Hung; Weng, Bi-Chuang; Wu, Chun-Chieh; Yang, Sheau-Fang; Wu, Deng-Chang; Wang, Yuan-Chuen

2014-02-12

Apigenin, one of the most common flavonoids, is abundant in celery, parsley, chamomile, passionflower, and other vegetables and fruits. Celery is recognized as a medicinal vegetable in Oriental countries to traditionally treat inflammation, swelling, blood pressure, serum lipid, and toothache. In this study, we investigated apigenin treatment effects on Helicobacter pylori-induced atrophic gastritis and gastric cancer progression in Mongolian gerbils. Five to eight-week-old Mongolian gerbils were inoculated with Helicobacter pylori for four weeks without (atrophic gastritis group) or with N'-methyl-N'-nitro-N-nitroso-guanidine (MNNG) (gastric cancer group) in drinking water, and were then rested for two weeks. During the 7th-32th (atrophic gastritis group) or the 7th-52th (gastric cancer group) weeks, they were given various doses (0-60 mg/kgbw/day) of apigenin. At the end of the 32th (atrophic gastritis group) or the 52th (atrophic gastritis group) week, all Mongolian gerbils were sacrificed using the CO2 asphyxia method. The histological changes of Helicobacter pylori colonization, neutrophil and monocyte infiltrations, and atrophic gastritis in both atrophic gastritis and gastric cancer Mongolian gerbils were examined using immunohistochemistry stain and Sydney System scoring. Apigenin treatments (30-60 mg/kgbw/day) effectively decreased atrophic gastritis (atrophic gastritis group) and dysplasia/gastric cancer (gastric cancer group) rates in Mongolian gerbils. Apigenin treatment (60 mg/kgbw/day) significantly decreased Helicobacter pylori colonization and Helicobacter pylori-induced histological changes of neutrophil and monocyte infiltrations and atrophic gastritis in both atrophic gastritis and gastric cancer Mongolian gerbils. Apigenin has the remarkable ability to inhibit Helicobacter pylori-induced atrophic gastritis and gastric cancer progression as well as possessing potent anti-gastric cancer activity. Copyright © 2013 Elsevier Ireland Ltd. All rights

Decreased hippocampal homoarginine and increased nitric oxide and nitric oxide synthase levels in rats parallel training in a radial arm maze.

Science.gov (United States)

Sase, Ajinkya; Nawaratna, Gayan; Hu, Shengdi; Wu, Guoyao; Lubec, Gert

2016-09-01

L-homoarginine (hArg) is derived from enzymatic guanidination of lysine. It was demonstrated that hArg is a substrate for nitric oxide (NO) synthesis, blocks lysine transport and inhibits the uptake of arginine into synaptosomes and modulates GABA responses ex vivo. As there is limited information on its physiological roles in the brain, the aim of the study was to show whether hippocampal or frontal lobe (FL) hArg is paralleling training in the radial arm maze (RAM) or NO formation. Hippocampi and FL of male Sprague-Dawley rats were taken from trained or yoked in a RAM. Then hArg and metabolites, NO and NO synthase (NOS) were determined by standard methods. The animals learned the task in the RAM showing significant reduction of working memory errors. hArg showed decreased levels in both brain regions of trained animals as compared to yoked animals. Nitrate plus nitrite (NOx) concentrations and NOS activity were significantly increased in hippocampi, F(1,36) = 170.5; P ≤ 0.0001 and FL, F(1,36) = 74.67; P ≤ 0.0001 of trained animals as compared to yoked animals. Levels of hArg were negatively correlated with NOx in hippocampus (r = -0.6355; P = 0.0483) but not in FL and with lysine in the FL (r = -0.6650; P = 0.0358). NOx levels were positively correlated with NOS in both the hippocampus (r = 0.7474; P = 0.0129) and FL (r = 0.9563; P ≤  0.0001). These novel findings indicate that hArg is linked to NO formation in hippocampus but not in FL and is paralleling spatial memory in the RAM.

Arginine substitution of a cysteine in transmembrane helix M8 converts Na+,K+-ATPase to an electroneutral pump similar to H+,K+-ATPase.

Science.gov (United States)

Holm, Rikke; Khandelwal, Jaanki; Einholm, Anja P; Andersen, Jens P; Artigas, Pablo; Vilsen, Bente

2017-01-10

Na + ,K + -ATPase and H + ,K + -ATPase are electrogenic and nonelectrogenic ion pumps, respectively. The underlying structural basis for this difference has not been established, and it has not been revealed how the H + ,K + -ATPase avoids binding of Na + at the site corresponding to the Na + -specific site of the Na + ,K + -ATPase (site III). In this study, we addressed these questions by using site-directed mutagenesis in combination with enzymatic, transport, and electrophysiological functional measurements. Replacement of the cysteine C932 in transmembrane helix M8 of Na + ,K + -ATPase with arginine, present in the H + ,K + -ATPase at the corresponding position, converted the normal 3Na + :2K + :1ATP stoichiometry of the Na + ,K + -ATPase to electroneutral 2Na + :2K + :1ATP stoichiometry similar to the electroneutral transport mode of the H + ,K + -ATPase. The electroneutral C932R mutant of the Na + ,K + -ATPase retained a wild-type-like enzyme turnover rate for ATP hydrolysis and rate of cellular K + uptake. Only a relatively minor reduction of apparent Na + affinity for activation of phosphorylation from ATP was observed for C932R, whereas replacement of C932 with leucine or phenylalanine, the latter of a size comparable to arginine, led to spectacular reductions of apparent Na + affinity without changing the electrogenicity. From these results, in combination with structural considerations, it appears that the guanidine + group of the M8 arginine replaces Na + at the third site, thus preventing Na + binding there, although allowing Na + to bind at the two other sites and become transported. Hence, in the H + ,K + -ATPase, the ability of the M8 arginine to donate an internal cation binding at the third site is decisive for the electroneutral transport mode of this pump.

Helical Propensity Affects the Conformational Properties of the Denatured State of Cytochrome c'.

Science.gov (United States)

Danielson, Travis A; Bowler, Bruce E

2018-01-23

Changing the helical propensity of a polypeptide sequence might be expected to affect the conformational properties of the denatured state of a protein. To test this hypothesis, alanines at positions 83 and 87 near the center of helix 3 of cytochrome c' from Rhodopseudomonas palustris were mutated to serine to decrease the stability of this helix. A set of 13 single histidine variants in the A83S/A87S background were prepared to permit assessment of the conformational properties of the denatured state using histidine-loop formation in 3 M guanidine hydrochloride. The data are compared with previous histidine-heme loop formation data for wild-type cytochrome c'. As expected, destabilization of helix 3 decreases the global stabilities of the histidine variants in the A83S/A87S background relative to the wild-type background. Loop stability versus loop size data yields a scaling exponent of 2.1 ± 0.2, similar to the value of 2.3 ± 0.2 obtained for wild-type cytochrome c'. However, the stabilities of all histidine-heme loops, which contain the helix 3 sequence segment, are increased in the A83S/A87S background compared to the wild-type background. Rate constants for histidine-heme loop breakage are similar for the wild-type and A83S/A87S variants. However, for histidine-heme loops that contain the helix 3 sequence segment, the rate constants for loop formation increase in the A83S/A87S background compared to the wild-type background. Thus, residual helical structure appears to stiffen the polypeptide chain slowing loop formation in the denatured state. The implications of these results for protein folding mechanisms are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): influence of variable amino acids on the degradation kinetics and reaction mechanisms.

Science.gov (United States)

He, Xuexiang; de la Cruz, Armah A; Hiskia, Anastasia; Kaloudis, Triantafyllos; O'Shea, Kevin; Dionysiou, Dionysios D

2015-05-01

Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O8(2-) and UV/HSO5(-). Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O8(2-) > UV/HSO5(-) > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

OCT2 and MATE1 Provide Bi-directional Agmatine Transport

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Winter, Tate N.; Elmquist, William F.; Fairbanks, Carolyn A.

2015-01-01

Agmatine is a biogenic amine (l-arginine metabolite) of potential relevance to several central nervous system (CNS) conditions. The identities of transporters underlying agmatine and polyamine disposition in mammalian systems are not well defined. The SLC-family organic cation transporters (OCT) OCT1 and OCT2 and multidrug and toxin extrusion transporter-1 (MATE1) are transport systems that may be of importance for the cellular disposition of agmatine and putrescine. We investigated the transport of [3H]-agmatine and [3H]-putrescine in human embryonic kidney (HEK293) cells stably-transfected with hOCT1-, hOCT2-, and hMATE1. Agmatine transport by hOCT1 and hOCT2 was concentration-dependent, whereas only hOCT2 demonstrated pH-dependent transport. hOCT2 exhibited a greater affinity for agmatine (Km = 1.84 ± 0.38 mM) than did hOCT1 (Km = 18.73 ± 4.86 mM). Putrescine accumulation was pH- and concentration-dependent in hOCT2-HEK cells (Km = 11.29 ± 4.26 mM) but not hOCT1-HEK cells. Agmatine accumulation, in contrast to putrescine, was significantly enhanced by hMATE1 over-expression, and was saturable (Km = 240 ± 31 μM; Vmax = 192 ± 10 pmol/min/mg protein). Intracellular agmatine was also trans-stimulated (effluxed) from hMATE1-HEK cells in the presence of an inward proton-gradient. The hMATE1-mediated transport of agmatine was inhibited by polyamines, the prototypical substrates MPP+ and paraquat, as well as guanidine and arcaine, but not l-arginine. These results suggest that agmatine disposition may be influenced by hOCT2 and hMATE1, two transporters critical in the renal elimination of xenobiotic compounds. PMID:21128598

Arginine kinase in the cladoceran Daphnia magna: cDNA sequencing and expression is associated with resistance to toxic Microcystis.

Science.gov (United States)

Lyu, Kai; Zhang, Lu; Zhu, Xuexia; Cui, Guilian; Wilson, Alan E; Yang, Zhou

2015-03-01

Nutrient loading derived from anthropogenic activities into lakes have increased the frequency, severity and duration of toxic cyanobacterial blooms around the world. Although herbivorous zooplankton are generally considered to be unable to control toxic cyanobacteria, populations of some zooplankton, including Daphnia, have been shown to locally adapt to toxic cyanobacteria and suppress cyanobacterial bloom formation. However, little is known about the physiology of zooplankton behind this phenomenon. One possible explanation is that some zooplankton may induce more tolerance by elevating energy production, thereby adding more energy allocation to detoxification expenditure. It is assumed that arginine kinase (AK) serves as a core in temporal and spatial adenosine triphosphate (ATP) buffering in cells with high fluctuating energy requirements. To test this hypothesis, we studied the energetic response of a single Daphnia magna clone exposed to a toxic strain of Microcystis aeruginosa, PCC7806. Arginine kinase of D. magna (Dm-AK) was successfully cloned. An ATP-gua PtransN domain which was described as a guanidine substrate specificity domain and an ATP-gua Ptrans domain which was responsible for binding ATP were both identified in the Dm-AK. Phylogenetic analysis of AKs in a range of arthropod taxa suggested that Dm-AK was as dissimilar to other crustaceans as it was to insects. Dm-AK transcript level and ATP content in the presence of M. aeruginosa were significantly lower than those in the control diet containing only the nutritious chlorophyte, Scenedesmus obliquus, whereas the two parameters in the neonates whose mothers had been previously exposed to M. aeruginosa were significantly higher than those of mothers fed with pure S. obliquus. These findings suggest that Dm-AK might play an essential role in the coupling of energy production and utilization and the tolerance of D. magna to toxic cyanobacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Evolving transpeptidase and hydrolytic variants of γ-glutamyl transpeptidase from Bacillus licheniformis by targeted mutations of conserved residue Arg109 and their biotechnological relevance.

Science.gov (United States)

Bindal, Shruti; Sharma, Sujata; Singh, Tej P; Gupta, Rani

2017-05-10

γ-Glutamyl transpeptidase (GGT) catalyzes the transfer of the γ-glutamyl moiety from donor compounds such as l-glutamine (Gln) and glutathione (GSH) to an acceptor. During the biosynthesis of various γ-glutamyl-containing compounds using GGT enzyme, auto-transpeptidation reaction leads to the formation of unwanted byproducts. Therefore, in order to alter the auto-transpeptidase activity of the GGT enzyme, the binding affinity of Gln should be modified. Structural studies of the Bacillus licheniformis GGT (BlGT) complexed with the glutamic acid has shown that glutamic acid has strong ionic interactions through its α-carboxlic group with the guanidine moiety of Arg109. This interaction appears to be an important contributor for the binding affinity of Gln. In view of this, six mutants of Bacillus licheniformis ER15 GGT (BlGGT) viz. Arg109Lys, Arg109Ser, Arg109Met, Arg109Leu, Arg109Glu and Arg109Phe were prepared. As seen from the structure of BlGT, the mutation of Arg109 to Lys109 may reduce the affinity for Gln to some extent, whereas the other mutations are expected to lower the affinity much more. Biophysical characterization and functional studies revealed that Arg109Lys mutant has increased transpeptidation activity and catalytic efficiency than the other mutants. The Arg109Lys mutant showed high conversion rates for l-theanine synthesis as well. Moreover, the Arg109Met mutant showed increased hydrolytic activity as it completely altered the binding of Gln at the active site. Also, the salt stability of the enzyme was significantly improved on replacing Arg109 by Met109 which is required for hydrolytic applications of GGTs in food industries. Copyright © 2017 Elsevier B.V. All rights reserved.

Stability of Curcuma longa rhizome lectin: Role of N-linked glycosylation.

Science.gov (United States)

Biswas, Himadri; Chattopadhyaya, Rajagopal

2016-04-01

Curcuma longa rhizome lectin, a mannose-binding protein of non-seed portions of turmeric, is known to have antifungal, antibacterial and α-glucosidase inhibitory activities. We studied the role of complex-type glycans attached to asparagine (Asn) 66 and Asn 110 to elucidate the role of carbohydrates in lectin activity and stability. Apart from the native lectin, the characteristics of a deglycosylated Escherichia coli expressed lectin, high-mannose oligosaccharides at both asparagines and its glycosylation mutants N66Q and N110Q expressed in Pichia pastoris, were compared to understand the relationship between glycosylation and activity. Far UV circular dichroism (CD) spectra, fluorescence emission maximum, hemagglutination assay show no change in secondary or tertiary structures or sugar-binding properties between wild-type and aforementioned recombinant lectins under physiological pH. But reduced agglutination activity and loss of tertiary structure are observed in the acidic pH range for the deglycosylated and the N110Q protein. In thermal and guanidine hydrochloride (GdnCl)-induced unfolding, the wild-type and high-mannose lectins possess higher stability compared with the deglycosylated recombinant lectin and both mutants, as measured by a higher Tm of denaturation or a greater free energy change, respectively. Reversibility experiments after thermal denaturation reveal that deglycosylated proteins tend to aggregate during thermal inactivation but the wild type shows a much greater recovery to the native state upon refolding. These results suggest that N-glycosylation in turmeric lectin is important for the maintenance of its proper folding upon changes in pH, and that the oligosaccharides help in maintaining the active conformation and prevent aggregation in unfolded or partially folded molecules. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Insulin-releasing action of the novel antidiabetic agent BTS 67 582.

Science.gov (United States)

McClenaghan, N H; Flatt, P R; Bailey, C J

1998-02-01

1. BTS 67582 (1,1-dimethyl-2-(2-morpholinophenyl)guanidine fumarate) is a novel antidiabetic agent with a short-acting insulin-releasing effect. This study examined its mode of action in the clonal B-cell line BRIN-BD11. 2. BTS 67582 increased insulin release from BRIN-BD11 cells in a concentration-dependent manner (10[-8] to 10[-4] M) at both non-stimulating (1.1 mM) and stimulating (16.7 mM) concentrations of glucose. 3. BTS 67582 (10[-4] M) potentiated the insulin-releasing effect of a depolarizing concentration of K+ (30 mM), whereas the K+ channel openers pinacidil (400 microM) and diazoxide (300 microM) inhibited BTS 67582-induced release. 4. Suppression of Ca+ channel activity with verapamil (20 microM) reduced the insulin-releasing effect of BTS 67582 (10[-4] M). 5. BTS 67582 (10[-4] M) potentiated insulin release induced by amino acids (10 mM), and enhanced the combined stimulant effects of glucose plus either the fatty acid palmitate (10 mM), or agents which raise intracellular cyclic AMP concentrations (25 microM forskolin and 1 mM isobutylmethylxanthine), or the cholinoceptor agonist carbachol (100 microM). 6. Inhibition of glucose-stimulated insulin release by adrenaline or noradrenaline (10 microM) was partially reversed by BTS 67582 (10[-4] M). 7. These data suggest that the insulin-releasing effect of BTS 67582 involves regulation of ATP-sensitive K+ channel activity and Ca2+ influx, and that the drug augments the stimulant effects of nutrient insulin secretagogues and agents which enhance adenylate cyclase and phospholipase C. BTS 67582 may also exert insulin-releasing effects independently of ATP-sensitive K+ channel activity.

Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

International Nuclear Information System (INIS)

Arnold, John

2015-01-01

The uranyl cation (UO 2 2+ ) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

Cementation of the solid radioactive waste with polymer-cement solutions using the method of impregnation

International Nuclear Information System (INIS)

Gorbunova, O.

2015-01-01

Cementation of solid radioactive waste (SRW), i.e. inclusion of solid radioactive waste into cement matrix without cavities - is one of the main technological processes used for conditioning low and intermediate level radioactive waste. At FSUE 'Radon' the industrialized method of impregnation has been developed and since 2003 has been using for cementation of solid radioactive waste. The technology is that the polymer-cement solution, having high penetrating properties, is supplied under pressure through a tube to the bottom of the container in which solid radioactive waste has preliminarily been placed. The polymer-cement solution is evenly moving upwards through the channels between the particles of solid radioactive waste, fills the voids in the bulk volume of the waste and hardens, forming a cement compound, the amount of which is equal to the original volume. The aim of the investigation was a selection of a cement solution suitable for SRW impregnation (including fine particles) without solution depletion and bottom layers stuffing. It has been chosen a polymer: PHMG (polyhexamethylene-guanidine), which is a stabilizing and water-retaining component of the cement solution. The experiments confirm that the polymer increases the permeability of the cement solution by a 2-2.5 factor, the viscosity by a 1.2 factor, the stability of the consistency by a 1.5-1.7 factor, and extends the operating range of the W/C ratio to 0.5-1.1. So it is possible to penetrate a volume of SRW bigger by a 1.5-2.0 factor. It has been proved, that PHMG polymer increases strength and frost-resistance of the final compounds by a 1.8-2.7 factor, and contributes to fast strength development at the beginning of hardening and it decreases Cs-137 leashing rate by a 1.5-2 factor

Long-term effects of the angiotensin-converting enzyme inhibitor enalapril on chronic heart failure. Examination by {sup 123}I-MIBG imaging

Energy Technology Data Exchange (ETDEWEB)

Soeki, Takeshi; Tamura, Yoshiyuki; Bandou, Kanji; Tanaka, Hideji; Takeichi, Naoki; Shinohara, Hisanori; Yui, Yasuko; Fukuda, Nobuo; Sui, Osamu [Zentsuji National Hospital, Kagawa (Japan)

1998-11-01

To examine the long-term effects of the angiotensin-converting enzyme (ACE) inhibitor enalapril on chronic heart failure, 10 patients (7 men and 3 women, mean age: 62{+-}11 years) with chronic stable heart failure, classified as New York Heart Association (NYHA) functional class 2-3 for more than 3 months, and a left ventricular ejection fraction less than 45% were treated with 2.5-5.0 mg of enalapril once a day for 3-15 months (mean 7 months). The causes of heart failure were old myocardial infarction (n=7), hypertension (n=2), and atrial fibrillation (n=1). Radioiodinated metaiodobenzyl guanidine ({sup 123}I-MIBG) imaging, radionuclide angiography, and treadmill exercise test were performed before and after the treatment. With enalapril treatment, left ventricular ejection fraction (LVEF) increased significantly from 38.3{+-}6.9% to 47.5{+-}14.7%; sub-maximal exercise time increased significantly from 205{+-}112 to 272{+-}120 seconds; the heart to mediastinum (H/M) ratio of {sup 123}I-MIBG increased significantly (early image: 1.99{+-}0.38 versus 2.20{+-}0.50; delayed image: 1.86{+-}0.44 versus 2.09{+-}0.51); and the washout rate of {sup 123}I-MIBG decreased slightly from 29.1{+-}9.1% to 25.4{+-}7.0%. The improvement rate of LVEF was significantly correlated with the improvement rates of the H/M ratio and washout rate after treatment with enalapril. Thus, the long-term effects of enalapril can be observed in the cardiac sympathetic nervous system, and {sup 123}I-MIBG imaging appears to be useful for evaluating the therapeutic effects of enalapril on the cardiac sympathetic nervous system in patients with chronic heart failure. (author)

Long-term effects of the angiotensin-converting enzyme inhibitor enalapril on chronic heart failure. Examination by 123I-MIBG imaging

International Nuclear Information System (INIS)

Soeki, Takeshi; Tamura, Yoshiyuki; Bandou, Kanji; Tanaka, Hideji; Takeichi, Naoki; Shinohara, Hisanori; Yui, Yasuko; Fukuda, Nobuo; Sui, Osamu

1998-01-01

To examine the long-term effects of the angiotensin-converting enzyme (ACE) inhibitor enalapril on chronic heart failure, 10 patients (7 men and 3 women, mean age: 62±11 years) with chronic stable heart failure, classified as New York Heart Association (NYHA) functional class 2-3 for more than 3 months, and a left ventricular ejection fraction less than 45% were treated with 2.5-5.0 mg of enalapril once a day for 3-15 months (mean 7 months). The causes of heart failure were old myocardial infarction (n=7), hypertension (n=2), and atrial fibrillation (n=1). Radioiodinated metaiodobenzyl guanidine ( 123 I-MIBG) imaging, radionuclide angiography, and treadmill exercise test were performed before and after the treatment. With enalapril treatment, left ventricular ejection fraction (LVEF) increased significantly from 38.3±6.9% to 47.5±14.7%; sub-maximal exercise time increased significantly from 205±112 to 272±120 seconds; the heart to mediastinum (H/M) ratio of 123 I-MIBG increased significantly (early image: 1.99±0.38 versus 2.20±0.50; delayed image: 1.86±0.44 versus 2.09±0.51); and the washout rate of 123 I-MIBG decreased slightly from 29.1±9.1% to 25.4±7.0%. The improvement rate of LVEF was significantly correlated with the improvement rates of the H/M ratio and washout rate after treatment with enalapril. Thus, the long-term effects of enalapril can be observed in the cardiac sympathetic nervous system, and 123 I-MIBG imaging appears to be useful for evaluating the therapeutic effects of enalapril on the cardiac sympathetic nervous system in patients with chronic heart failure. (author)

Use of myocardial tomo-scintigraphy by {sup 123}I - MIBG in right ventricle arrhythmia-gen dysplasia; Interet de la tomoscintigraphie myocardique a la {sup 123}I - MIBG dans la dysplasie arrythmogene du ventricule droit

Energy Technology Data Exchange (ETDEWEB)

Agostini, D.; Manrique, A.; Darlas, Y. [Service de Medecine Nucleaire, CHU Cote de Nacre, Caen (France); Loiselet, P.; Scanu, P.; Grollier, G.; Potier, J.C. [Service de Cardiologie, CHU Cote de Nacre, Caen (France); Bouvard, G. [Service de Medecine Nucleaire, CHU Cote de Nacre, Caen (France)

1997-12-31

The dysfunction of myocardial sympathetic system was implied in occurrence of ventricular arrhythmias in patients with a right ventricle arrhythmia-gen dysplasia (RVAD). The goal of this study is to evaluate the myocardial pre-synaptic adrenergic regional function by using the cardiac tomo-scintigraphy with {sup 123}I - meta-iodo-benzyl-guanidine (MIBG). Fourteen patients (12 M, 2 F, age: 46{+-} 13) in whom the disease`s diagnosis was done on the basis of the parameters of European Task Force (electric, angiographic, histologic), were studied. Six healthy subjects (32 {+-} 12 years) were at the same time studied as control group. Each patient benefited by an at-rest tomo-scintigraphy by {sup 201}Tl to eliminate any hypo-perfusion which could hinder the interpretation of MIBG fixation. A 48 h delay was necessary between the two isotopic examinations. After blocking the thyroid by Lugol fort, an at-rest tomo-scintigraphy by {sup 123}I - MIBG was effected 4 h after the injection IV of 259 MBq of tracer following a classical acquisition of a myocardial tomography with a tracer-adopted collimator (Elscint camera). Global and regional evaluations of the cardiac adrenergic neuronal function were effected by using the cardio-mediastinal ratio (CMR) and the circumferential profile, respectively, for the localization, extension and amplitude of regional adrenergic defects. The CMR is within the normal limits (236 {+-} 39% vs 234 {+-} 14% in healthy subjects). The adrenergic defects are present in 11/14 patients (a reduction of 50% of capture of MIBG as compared with the control group, < average - 2 ET) in the anterior and lateral regions of left ventricle. In conclusion, the tomo-scintigraphy by {sup 123}I - MIBG allows the detecting of presence of a sympathetic dys-innervation of left ventricle in patients afflicted with RVAD

Simple detection of hepatitis C virus using {sup 125}I-2'-deoxyuridine triphosphate and gamma counter

Energy Technology Data Exchange (ETDEWEB)

Lee, Soo Jin; Ahn, S. H.; Chung, W. S.; Woo, K. S.; Lim, S. J.; Choi, C. W.; Lim, S. M. [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

2000-07-01

Hepatitis C Virus (HCV) is the major cause of post transfusion and sporadic non A, non B hepatitis. Current infection of HCV can be detected by PCR method. Using PCR, it has been possible to detect HCV viremia prior to immunological sero-conversion and to detect fluctuation of viremia in antibody-positive chronic HCV patients undergoing therapy with interferon. In this study, we established the simple method to detect HCV DNA by incorporation of {sup 125}I-deoxyuridine triphosphate(dUTP) into DNA during the PCR, and counted the radioactivity of PCR product by gamma counter. {sup 125}I-2'-deoxyuridine 5'-triphosphate was prepared, and incorporated into DNA during PCR. dUTP was radiolabeled by the iododemercuration of 5-mercuri intermediate. Iododemercuration labeling was completed with 98% yield and the obtained product was incorporated into DNA without further purification. After incorporation, covalently bonded radioiodine substituent was remained stable during PCR procedure HCV positive standard and positive patient sera in immunological assay were centrifuged. HCV RNA is isolated from by GTC(Guanidine Thiocyanate) and phenol/chloroform extraction method and synthesized complementary DNA by using reverse transcriptase. The '1{sup 25}I-dUTP was incorporated into HCV C DNA during PCR. PCR product purified by fiber matrix column and counted by gamma counter. PCR products were electrophoresized, and autoradiography image obtained. Amplified HCV DNA by {sup 125}I-dUTP PCR obtained the band on the gel by electrophoresis and autoradiography at the same position. In patient sera, radioactivity of HCV positive sample was 8 times higher than HCV negative viremia sample. We established HCV detection method using {sup 125}I-dUTP. {sup 125}I-dUTP PCR detection of HCV is convenient and reporducible.

Heterogeneous binding of sigma radioligands in the rat brain and liver

International Nuclear Information System (INIS)

Ross, S.B.

1991-01-01

The binding of four sigma receptor ligands, 3 H-(+)-N-allyl-N-normetazocine ( 3 H-(+)-SKF 10,047), 3 H-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ( 3 H-(+)-3-PPP), 3 H-haloperidol and 3 H-N,N'-di(o-totyl)guanidine ( 3 H-DTG), and the cytochrome P450IID6 ligand and dopamine uptake inhibitor 3 H-1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine ( 3 H-GBR 12935) to membranal preparations of rat liver or whole rat brain was examined regarding kinetical properties and inhibition by various compounds with affinity for sigma binding sites or cytochrome P-450. In rat brain the density of binding sites was increased in order (+)-SKF 10,047 3 H-(+)-SKF 10,047 there were quite marked differences between the ligands studied. Multiple binding sites were also indicated by the low Hill coefficients found for most of the compounds studied. It was found that the cytochrome P-450 inhibitor proadifen (SKF 525A), like haloperidol, was a potent inhibitor of the binding of 3 H-(+)-SKF 10,047, 3 H-(+)-3-PPP and 3 H-haloperidol to the liver and brain preparations, less active in inhibiting the binding of 3 H-DTG and least effective on the binding of 3 H-GBR 12935. Another cytochrome P-450 inhibitor, L-lobeline, was particularly potent in inhibiting the binding of 3 H-DTG but was also quite potent inhibitor of the binding of the other sigma ligands. It was less potent in inhibiting the binding of 3 H-GBR 12935. The binding of the latter ligand was potently inhibited by the analogous compound GBR 12909 but of the other compounds examined only L-lobeline, proadifen, haloperidol, DTG and (+)-3-PPP had IC50 values below 10 μM. The possibility that the sigma binding sites are identical with some subforms of cytochrome P-450 is discussed. (author)

Clusterin levels are increased in Alzheimer's disease and influence the regional distribution of Aβ.

Science.gov (United States)

Miners, J Scott; Clarke, Polly; Love, Seth

2017-05-01

Clusterin, also known as apoJ, is a lipoprotein abundantly expressed within the CNS. It regulates Aβ fibril formation and toxicity and facilitates amyloid-β (Aβ) transport across the blood-brain barrier. Genome-wide association studies have shown variations in the clusterin gene (CLU) to influence the risk of developing sporadic Alzheimer's disease (AD). To explore whether clusterin modulates the regional deposition of Aβ, we measured levels of soluble (NP40-extracted) and insoluble (guanidine-HCl-extracted) clusterin, Aβ40 and Aβ42 by sandwich ELISA in brain regions with a predilection for amyloid pathology-mid-frontal cortex (MF), cingulate cortex (CC), parahippocampal cortex (PH), and regions with little or no pathology-thalamus (TH) and white matter (WM). Clusterin level was highest in regions with plaque pathology (MF, CC, PH and PC), approximately mirroring the regional distribution of Aβ. It was significantly higher in AD than controls, and correlated positively with Aβ42 and insoluble Aβ40. Soluble clusterin level rose significantly with severity of cerebral amyloid angiopathy, and in MF and PC regions was highest in APOE ɛ4 homozygotes. In the TH and WM (areas with little amyloid pathology) clusterin was unaltered in AD and did not correlate with Aβ level. There was a significant positive correlation between the concentration of clusterin and the regional levels of insoluble Aβ42; however, the molar ratio of clusterin : Aβ42 declined with insoluble Aβ42 level in a region-dependent manner, being lowest in regions with predilection for Aβ plaque pathology. Under physiological conditions, clusterin reduces aggregation and promotes clearance of Aβ. Our findings indicate that in AD, clusterin increases, particularly in regions with most abundant Aβ, but because the increase does not match the rising level of Aβ42, the molar ratio of clusterin : Aβ42 in those regions falls, probably contributing to Aβ deposition within the tissue. © 2016

First external quality assurance program for bloodstream Real-Time PCR monitoring of treatment response in clinical trials of Chagas disease.

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Juan C Ramírez

Full Text Available Real-Time PCR (qPCR testing is recommended as both a diagnostic and outcome measurement of etiological treatment in clinical practice and clinical trials of Chagas disease (CD, but no external quality assurance (EQA program provides performance assessment of the assays in use. We implemented an EQA system to evaluate the performance of molecular biology laboratories involved in qPCR based follow-up in clinical trials of CD. An EQA program was devised for three clinical trials of CD: the E1224 (NCT01489228, a pro-drug of ravuconazole; the Sampling Study (NCT01678599, that used benznidazole, both conducted in Bolivia; and the CHAGASAZOL (NCT01162967, that tested posaconazole, conducted in Spain. Four proficiency testing panels containing negative controls and seronegative blood samples spiked with 1, 10 and 100 parasite equivalents (par. eq./mL of four Trypanosoma cruzi stocks, were sent from the Core Lab in Argentina to the participating laboratories located in Bolivia and Spain. Panels were analyzed simultaneously, blinded to sample allocation, at 4-month intervals. In addition, 302 random blood samples from both trials carried out in Bolivia were sent to Core Lab for retesting analysis. The analysis of proficiency testing panels gave 100% of accordance (within laboratory agreement and concordance (between laboratory agreement for all T. cruzi stocks at 100 par. eq./mL; whereas their values ranged from 71 to 100% and from 62 to 100% at 1 and 10 par. eq./mL, respectively, depending on the T. cruzi stock. The results obtained after twelve months of preparation confirmed the stability of blood samples in guanidine-EDTA buffer. No significant differences were found between qPCR results from Bolivian laboratory and Core Lab for retested clinical samples. This EQA program for qPCR analysis of CD patient samples may significantly contribute to ensuring the quality of laboratory data generated in clinical trials and molecular diagnostics laboratories of

Synthesis, X-ray crystal structures, and phosphate ester cleavage properties of bis(2-pyridylmethyl)amine copper(II) complexes with guanidinium pendant groups.

Science.gov (United States)

Belousoff, Matthew J; Tjioe, Linda; Graham, Bim; Spiccia, Leone

2008-10-06

Three new derivatives of bis(2-pyridylmethyl)amine (DPA) featuring ethylguanidinium (L (1)), propylguanidinium (L (2)), or butylguanidinium (L (3)) pendant groups have been prepared by the reaction of N, N- bis(2-pyridylmethyl)alkane-alpha,omega-diamines with 1 H-pyrazole-1-carboxamidine hydrochloride. The corresponding mononuclear copper(II) complexes were prepared by reacting the ligands with copper(II) nitrate and were isolated as [Cu(LH (+))(OH 2)](ClO 4) 3. xNaClO 4. yH 2O ( C1: L = L (1), x = 2, y = 3; C2: L = L (2), x = 2, y = 4; C3: L = L (3), x = 1, y = 0) following cation exchange purification. Recrystallization yielded crystals of composition [Cu(LH (+))(X)](ClO 4) 3.X ( C1': L = L (1), X = MeOH; C2': L = L (2), X = H 2O; C3': L = L (3), X = H 2O), which were suitable for X-ray crystallography. The crystal structures of C1', C2', and C3' indicate that the DPA moieties of the ligands coordinate to the copper(II) centers in a meridional fashion, with a water or methanol molecule occupying the fourth basal position. Weakly bound perchlorate anions located in the axial positions complete the distorted octahedral coordination spheres. The noncoordinating, monoprotonated guanidinium groups project away from the Cu(II)-DPA units and are involved in extensive charge-assisted hydrogen-bonding interactions with cocrystallized water/methanol molecules and perchlorate anions within the crystal lattices. The copper(II) complexes were tested for their ability to promote the cleavage of two model phosphodiesters, bis( p-nitrophenyl)phosphate (BNPP) and uridine-3'- p-nitrophenylphosphate (UpNP), as well as supercoiled plasmid DNA (pBR 322). While the presence of the guanidine pendants was found to be detrimental to BNPP cleavage efficiency, the functionalized complexes were found to cleave plasmid DNA and, in some cases, the model ribose phosphate diester, UpNP, at a faster rate than the parent copper(II) complex of DPA.

A NEW METHOD FOR PREPARING 6-NITRO-2-(4-BOC-PIPERAZIN-1-YL-3H-QUINAZOLIN-4-ONE

Directory of Open Access Journals (Sweden)

A. Yu. Kornylov

2017-11-01

Full Text Available The 2-amino-3H-quinazolin-4-one scaffold is found in a large number of molecules with physiological significance and pharmaceutical utility. Previously we synthesized a series of potent antagonists of fibrinogen receptor, derivatives of 2-(piperazin-1-yl-3H-quinazolin-4-one. The key building block for preparing the above series of compounds is 6-amino-2-(4-Boc-piperazin-1-yl-3H-quinazolin-4-one, which was synthesized by hydrogenation of 6-nitro-2-(4-Boc-piperazin-1-yl-3H-quinazolin-4-one. In turn, the nitro derivative was obtained starting from isatoic anhydride in four stages, by a method that can be considered classical, but difficult. The purpose of this work is to simplify the preparation of 6-nitro-2-(4-Boc-piperazin-1-yl-3H-quinazolin-4-one. We proposed an effective method for the synthesis of 6-nitro-2-(4-Boc-piperazin-1-yl-3H-quinazolin-4-one based on a sequential process, C-N cross-coupling and intramolecular amidation. As the arylhalogenide, 2-bromo-5-nitrobenzoic acid methyl ester was used, as the N-nucleophile, 4-Boc-piperazine-1-carboxamidine, a guanidine derivative, was used. In the study, we used two types of catalytic systems, which both gave good results. The application of the third generation of Palladacycleprecatalyst –[(4,5-Bis(diphenylphosphino-9,9-dimethylxanthene-2-(2′-amino-1,1′-biphenyl] palladium(II methanesulfonate, leads to the production of the target product in a high yield, in comparison with the use of the catalytic system: precatalyst – Tris(dibenzylideneacetone dipalladium(0 chloroform adduct and Buchwald Ligands – 4,5-Bis(diphenylphosphino-9,9-dimethylxanthene. The structure of the title compound was confirmed by spectroscopy 1H and 13C NMR, and FAB mass spectrometry methods, purity was controlled by HPLC. This method has potential implications for the design of various 2-amino-3H-quinazolin-4-ones.

A complex of cardiac cytochrome c1 and cytochrome c.

Science.gov (United States)

Chiang, Y L; Kaminsky, L S; King, T E

1976-01-10

The interactions of cytochrome c1 and cytochrome c from bovine cardiac mitochondria were investigated. Cytochrome c1 and cytochrome c formed a 1:1 molecular complex in aqueous solutions of low ionic strength. The complex was stable to Sephadex G-75 chromatography. The formation and stability of the complex were independent of the oxidation state of the cytochrome components as far as those reactions studied were concerned. The complex was dissociated in solutions of ionic strength higher than 0.07 or pH exceeding 10 and only partially dissociated in 8 M urea. No complexation occurred when cytochrome c was acetylated on 64% of its lysine residues or photooxidized on its 2 methionine residues. Complexes with molecular ratios of less than 1:1 (i.e. more cytochrome c) were obtained when polymerized cytochrome c, or cytochrome c with all lysine residues guanidinated, or a "1-65 heme peptide" from cyanogen bromide cleavage of cytochrome c was used. These results were interpreted to imply that the complex was predominantly maintained by ionic interactions probably involving some of the lysine residues of cytochrome c but with major stabilization dependent on the native conformations of both cytochromes. The reduced complex was autooxidizable with biphasic kinetics with first order rate constants of 6 X 10(-5) and 5 X U0(-5) s-1 but did not react with carbon monoxide. The complex reacted with cyanide and was reduced by ascorbate at about 32% and 40% respectively, of the rates of reaction with cytochrome c alone. The complex was less photoreducible than cytochrome c1 alone. The complex exhibited remarkably different circular dichroic behavior from that of the summation of cytochrome c1 plus cytochrome c. We concluded that when cytochromes c1 and c interacted they underwent dramatic conformational changes resulting in weakening of their heme crevices. All results available would indicate that in the complex cytochrome c1 was bound at the entrance to the heme crevice of

Enhancing the performance of dye-sensitized solar cells by incorporating nanomica in gel electrolytes☆

KAUST Repository

Lai, Yi-Hsuan; Lin, Chia-Yu; Chen, Jian-Ging; Wang, Chun-Chieh; Huang, Kuan-Chieh; Liu, Ken-Yen; Lin, King-Fu; Lin, Jiang-Jen; Ho, Kuo-Chuan

2010-01-01

Gel-type dye-sensitized solar cells (DSSCs) were fabricated with 5.0 wt% polyvinyidene fluoride-co-hexafluoro propylene (PVDF-HFP) in methoxy propionitrile (MPN) as gel polymer electrolyte (GPE), 1-butyl-3-methylimidazolium iodide (BMII)/iodine (I2) as redox couple, 4-tertiary butyl pyridine (TBP) and guanidine thiocyanate as additives. The incorporation of alkyl-modified nanomica (AMNM) in the PVDF-HFP gel electrolytes caused the reduction of crystallization of PVDF-HFP, which was confirmed by X-ray diffraction (XRD) analysis. The short-circuit current density (JSC) of the cell increased due to the decrease of diffusion resistance, as judged by the electrochemical impedance spectra (EIS) analysis, while the open-circuit voltage (VOC) remained almost the same. As the loading of AMNM in the PVDF-HFP gel electrolyte was increased to 3.0 wt%, the JSC and power conversion efficiency (η) of the cells increased from 8.3 to 13.6 mA/cm2 and 3.5% to 5.7%, respectively. However, the JSC decreased as the loading of AMNM exceeded 3.0 wt%. At higher AMNM loadings, nanomica acted as a barrier interface between the electrolyte and the dye molecules to hinder electron transfer, and thus reducing the cell's photocurrent density. Furthermore, the DSSCs fabricated by dispersing polymethyl methacrylate (PMMA) microspheres in the TiO2 electrode with the GPE containing 3.0 wt% AMNM improved the η to 6.70%. The TiO2 films would exhibit larger porosity by blending with PMMA, leading the penetration of GPEs into the porous TiO2 easier, thus improving the contact between the dye-adsorbed TiO2 surfaces and the GPEs, as characterized by EIS. Moreover, the η of gel-type DSSCs with a 25 μm thickness of surlyn reached 7.96% as compared with 6.70% for the DSSCs with a 60 μm surlyn. © 2009 Elsevier B.V. All rights reserved.

Hydrogen-exchange kinetics of the indole NH proton of the buried tryptophan in the constant fragment of the immunoglobulin light chain

International Nuclear Information System (INIS)

Kawata, Y.; Goto, Y.; Hamaguchi, K.; Hayashi, F.; Kobayashi, Y.; Kyogoku, Y.

1988-01-01

The constant fragment of the immunoglobulin light chain (type λ) has two trytophyl residues at positions 150 and 187. Trp-150 is buried in the interior, and Trp-187 lies on the surface of the molecule. The hydrogen-deuterium exchange kinetics of the indole NH proton Trp-150 were studied at various pH values at 25 0 C by 1 H nuclear magnetic resonance. Exchange rates were approximately first order in hydroxyl ion dependence above pH 8, were relatively independent of pH between pH 7 and 8, and decreased below pH 7. On the assumption that the exchange above pH 8 proceeds through local fluctuations of the protein molecule, the exchange rates between pH 7 and 8 through global unfolding were estimated. The exchange rate constant within this pH range at 25 0 C thus estimated was consistent with that of the global unfolding of the constant fragment under the same conditions as those reported previously. The activation energy for the exchange process at pH 7.8 was the same as that for the unfolding process by 2 M guanidine hydrochloride. The exchange rates of backbone NH protons were almost the same as that of the indole NH proton of Trp-150 at pH 7.l. These observations also indicated that the exchange between pH 7 and 8 occurs through global unfolding of the protein molecule and is rate-limited by the unfolding. At around pH 9, on the other hand, the activation energy for the exchange process of the indole NH proton of Trp-150 was smaller than that for the unfolding process, and the exchange rates differed according to the different signals of backbone NH protons. These findings together with the pH dependence of the rate constant indicated that exchange due to local fluctuations is predominant above pH 8

Minocycline Blocks Asthma-associated Inflammation in Part by Interfering with the T Cell Receptor-Nuclear Factor κB-GATA-3-IL-4 Axis without a Prominent Effect on Poly(ADP-ribose) Polymerase*

Science.gov (United States)

Naura, Amarjit S.; Kim, Hogyoung; Ju, Jihang; Rodriguez, Paulo C.; Jordan, Joaquin; Catling, Andrew D.; Rezk, Bashir M.; Elmageed, Zakaria Y. Abd; Pyakurel, Kusma; Tarhuni, Abdelmetalab F.; Abughazleh, Mohammad Q.; Errami, Youssef; Zerfaoui, Mourad; Ochoa, Augusto C.; Boulares, A. Hamid

2013-01-01

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N′-nitro-N-nitroso-guanidine-treated mice or H2O2-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production. PMID:23184953

Naked mole-rat acid-sensing ion channel 3 forms nonfunctional homomers, but functional heteromers.

Science.gov (United States)

Schuhmacher, Laura-Nadine; Callejo, Gerard; Srivats, Shyam; Smith, Ewan St John

2018-02-02

Acid-sensing ion channels (ASICs) form both homotrimeric and heterotrimeric ion channels that are activated by extracellular protons and are involved in a wide range of physiological and pathophysiological processes, including pain and anxiety. ASIC proteins can form both homotrimeric and heterotrimeric ion channels. The ASIC3 subunit has been shown to be of particular importance in the peripheral nervous system with pharmacological and genetic manipulations demonstrating a role in pain. Naked mole-rats, despite having functional ASICs, are insensitive to acid as a noxious stimulus and show diminished avoidance of acidic fumes, ammonia, and carbon dioxide. Here we cloned naked mole-rat ASIC3 (nmrASIC3) and used a cell-surface biotinylation assay to demonstrate that it traffics to the plasma membrane, but using whole-cell patch clamp electrophysiology we observed that nmrASIC3 is insensitive to both protons and the non-proton ASIC3 agonist 2-guanidine-4-methylquinazoline. However, in line with previous reports of ASIC3 mRNA expression in dorsal root ganglia neurons, we found that the ASIC3 antagonist APETx2 reversibly inhibits ASIC-like currents in naked mole-rat dorsal root ganglia neurons. We further show that like the proton-insensitive ASIC2b and ASIC4, nmrASIC3 forms functional, proton-sensitive heteromers with other ASIC subunits. An amino acid alignment of ASIC3s between 9 relevant rodent species and human identified unique sequence differences that might underlie the proton insensitivity of nmrASIC3. However, introducing nmrASIC3 differences into rat ASIC3 (rASIC3) produced only minor differences in channel function, and replacing the nmrASIC3 sequence with that of rASIC3 did not produce a proton-sensitive ion channel. Our observation that nmrASIC3 forms nonfunctional homomers may reflect a further adaptation of the naked mole-rat to living in an environment with high-carbon dioxide levels. © 2018 by The American Society for Biochemistry and Molecular

Avidity of anti-malarial antibodies inversely related to transmission intensity at three sites in Uganda.

Science.gov (United States)

Ssewanyana, Isaac; Arinaitwe, Emmanuel; Nankabirwa, Joaniter I; Yeka, Adoke; Sullivan, Richard; Kamya, Moses R; Rosenthal, Philip J; Dorsey, Grant; Mayanja-Kizza, Harriet; Drakeley, Chris; Greenhouse, Bryan; Tetteh, Kevin K A

2017-02-10

People living in malaria endemic areas acquire protection from severe malaria quickly, but protection from clinical disease and control of parasitaemia is acquired only after many years of repeated infections. Antibodies play a central role in protection from clinical disease; however, protective antibodies are slow to develop. This study sought to investigate the influence of Plasmodium falciparum exposure on the acquisition of high-avidity antibodies to P. falciparum antigens, which may be associated with protection. Cross-sectional surveys were performed in children and adults at three sites in Uganda with varied P. falciparum transmission intensity (entomological inoculation rates; 3.8, 26.6, and 125 infectious bites per person per year). Sandwich ELISA was used to measure antibody responses to two P. falciparum merozoite surface antigens: merozoite surface protein 1-19 (MSP1-19) and apical membrane antigen 1 (AMA1). In individuals with detectable antibody levels, guanidine hydrochloride (GuHCl) was added to measure the relative avidity of antibody responses by ELISA. Within a site, there were no significant differences in median antibody levels between the three age groups. Between sites, median antibody levels were generally higher in the higher transmission sites, with differences more apparent for AMA-1 and in ≥5 year group. Similarly, median avidity index (proportion of high avidity antibodies) showed no significant increase with increasing age but was significantly lower at sites of higher transmission amongst participants ≥5 years of age. Using 5 M GuHCl, the median avidity indices in the ≥5 year group at the highest and lowest transmission sites were 19.9 and 26.8, respectively (p = 0.0002) for MSP1-19 and 12.2 and 17.2 (p = 0.0007) for AMA1. Avidity to two different P. falciparum antigens was lower in areas of high transmission intensity compared to areas with lower transmission. Appreciation of the mechanisms behind these findings as

Non-invasive ancient DNA protocol for fluid-preserved specimens and phylogenetic systematics of the genus Orestias (Teleostei: Cyprinodontidae).

Science.gov (United States)

Garrigos, Yareli Esquer; Hugueny, Bernard; Koerner, Kellie; Ibañez, Carla; Bonillo, Celine; Pruvost, Patrice; Causse, Romain; Cruaud, Corinne; Gaubert, Philippe

2013-01-01

Specimens stored in museum collections represent a crucial source of morphological and genetic information, notably for taxonomically problematic groups and extinct taxa. Although fluid-preserved specimens of groups such as teleosts may constitute an almost infinite source of DNA, few ancient DNA protocols have been applied to such material. In this study, we describe a non-invasive Guanidine-based (GuSCN) ancient DNA extraction protocol adapted to fluid-preserved specimens that we use to re-assess the systematics of the genus Orestias (Cyprinodontidae: Teleostei). The latter regroups pupfishes endemic to the inter-Andean basin that have been considered as a 'species flock', and for which the morphology-based taxonomic delimitations have been hotly debated. We extracted DNA from the type specimens of Orestias kept at the Muséum National d'Histoire Naturelle of Paris, France, including the extinct species O. cuvieri. We then built the first molecular (control region [CR] and rhodopsin [RH]) phylogeny including historical and recently collected representatives of all the Orestias complexes as recognized by Parenti (1984a): agassizii, cuvieri, gilsoni and mulleri. Our ancient DNA extraction protocol was validated after PCR amplification through an approach based on fragment-by-fragment chimera detection. After optimization, we were able to amplify Titicaca. We could not recover the reciprocal monophyly of any of the 15 species or morphotypes that were considered in our analyses, possibly due to incomplete lineage sorting and/or hybridization events. As a consequence, our results starkly question the delineation of a series of diagnostic characters listed in the literature for Orestias. Although not included in our phylogenetic analysis, the syntype of O. jussiei could not be assigned to the agassizii complex as newly defined. The CR sequence of the extinct O. cuvieri was recovered within the cuvieri clade (same haplotype as one representative of O. pentlandii), so

{sup 123}I-{beta}-methyl-iodophenyl-pentadecanoic acid myocardial scintigraphy in diabetic patients without overt ischemic heart disease

Energy Technology Data Exchange (ETDEWEB)

Shinmura, Ken; Tani, Masato; Suganuma, Yukako; Hasegawa, Hiroshi; Kawamura, Masatoshi; Nakamura, Yoshiro; Hashimoto, Jun; Kubo, Atsushi [Keio Univ., Tokyo (Japan). School of Medicine

1995-07-01

We evaluated {sup 123}I-{beta}-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial scintigraphy in 15 diabetes mellitus patients without overt coronary heart disease. Patients with overt coronary heart disease were excluded by careful history taking, resting electrocardiography, treadmill exercise testing echocardiography and resting {sup 201}Tl scintigraphy. Patients with remarkably impaired left ventricular (LV) systolic function (%FS<30%) were also excluded. BMIPP uptake scores as the ratio of heart/mediastinum (H/M) and liver/mediastinum (L/M) at 20 minutes after injection were analyzed and compared with clinical profile, serum parameters, and LV parameters obtained from echocardiography. Five of the 15 patients showed abnormal BMIPP images; two patients showed a decreased uptake in the inferior segments, while three showed a diffuse decrease in BMIPP uptake. Body mass index (BMI), fasting blood sugar (FBS), HbA1c, IRI, and LV end-diastolic diameter (LVEDD) were higher in these five patients with abnormal BMIPP findings (abnormal BMIPP group vs normal BMIPP group, BMI: 29 vs 23 kg/m{sup 2}, FBS: 178 vs 114 mg/dl, HbA1c: 7.6 vs 6.2%, IRI: 18.5 vs 9.5 {mu}U/ml, LVEDD: 52 vs 44 mm). {sup 123}I-metaiodobenzyl-guanidine (MIBG) scintigraphy in the 5 patients with abnormal BMIPP uptake showed more severe defects than in the 10 patients with normal BMIPP imaging. BMIPP scintigraphy demonstrated a significant correlation between H/M and L/M by BMIPP (r=0.74). Correlation between H/M by BMIPP scintigraphy and clinical parameters (BMI, systolic blood pressure, FBS, HbA1c, IRI) were found, suggesting that diabetes mellitus patients without over coronary heart disease show abnormal BMIPP imaging when their general glucose utility and {sup 123}I-MIBG uptake are severely impaired (progression of insulin resistance and sympathetic nerve involvement). BMIPP scintigraphy may be useful in investigating the pathogenesis and subclinical abnormality of diabetic heart. (J.P.N.).

Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase.

Science.gov (United States)

Naura, Amarjit S; Kim, Hogyoung; Ju, Jihang; Rodriguez, Paulo C; Jordan, Joaquin; Catling, Andrew D; Rezk, Bashir M; Abd Elmageed, Zakaria Y; Pyakurel, Kusma; Tarhuni, Abdelmetalab F; Abughazleh, Mohammad Q; Errami, Youssef; Zerfaoui, Mourad; Ochoa, Augusto C; Boulares, A Hamid

2013-01-18

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N'-nitro-N-nitroso-guanidine-treated mice or H(2)O(2)-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production.

High quality DNA from human papillomavirus (HPV for PCR/RFLPs

Directory of Open Access Journals (Sweden)

Denise Wanderlei-Silva

2005-01-01

Full Text Available The analysis of DNA in clinical samples for a secure diagnostic has become indispensable nowadays. Techniques approaching isolation of high molecular weigth DNA of HPV could lead to efficient amplification and early clinical diagnosis of the virus DNA by PCR (polymerase chain reaction. We describe a fast, non-toxical, efficient and cheap method for DNA isolation of human papilloma virus (HPV from cervical smears using guanidine (DNAzol solution. A 450 bp DNA band correponding to the late region (L1 of the virus genome was detected by PCR, showing that the DNAzol extraction soluction generated a good viral DNA yield. The electrophoretic pattern after digestion with restriction endonucleases (RFLPs/PCR revealed the predominance of HPV-16 and HPV-33 in the samples from the State of Alagoas, Brazil.A detecção de DNA em amostras clínicas visando um diagnóstico mais seguro vem se tornando uma prática comum em laboratórios de análise clínica. Metodologias que objetivem o isolamento de DNA de alto peso molecular de HPV podem levar a uma amplificação precisa e diagnose precoce do DNA do vírus por PCR (reação de polimerase em cadeia. Nós descrevemos um método para o isolamento do DNA do vírus do papiloma humano de amostras cervicais utilizando o detergente guanidina (solução DNAzol. O método foi rápido, não-tóxico e eficiente. Uma banda de DNA de 450 pb correspondente à região tardia (L1 do genoma viral foi detectada por PCR, mostrando que a extração com DNAzol gerou quantidade suficiente de DNA para análise. O padrão eletroforético, após digestão com endonucleases de restrição (RFLPs/PCR, revelou predominância de HPV 16 e HPV-33 nas amostras no Estado de Alagoas, Brasil.