Guanidine Solution Research Articles

Geopolymers made using organic bases. Part I: Synthesis and atomic structure

AbstractGeopolymers can act as a facile forming route to aluminosilicate ceramic composites due to being processed as fluids rather than as powders. However, the compositions available via typical alkali geopolymers are limited by the presence of alkali cations, introduced by the alkali silicate solution precursors. In order to expand the ceramic compositions that are accessible by geopolymer processing, this study explored the use of three strong organic bases (guanidine, tetramethylguanidine [TMG], and tetramethylammonium hydroxide [TMAOH]) as alternatives to inorganic alkali hydroxides in geopolymer synthesis. Silicate solutions were able to be produced with all three bases and favorable silica speciation was identified in the guanidine and TMG silicate solutions. Monolithic bodies were produced using guanidine and TMAOH, while no TMG samples hardened. By 27Al and 29Si nuclear magnetic resonance spectroscopy and powder X‐ray diffraction, the guanidine samples were determined to be structurally similar to those made using sodium hydroxide and hence can be called geopolymers, while the solids made with TMAOH were not structurally similar to sodium geopolymers and contained one or more unknown phases. This study has demonstrated that geopolymers can be made using organic bases rather than alkali hydroxides and that the speciation of dissolved silica alone does not indicate that an organic base silicate solution will be reactive.

Applicability of 2,4-dinitrophenylhydrazine (DNPH) method of protein oxidative damage measurement in the seminal plasma of canine ( Canis lupus familiaris) and stallion ( Equus caballus).

Seminal plasma (SP) proteins are responsible for sperm functional quality. Developing a reliable method to determine the degree of oxidative damage of these proteins is important for establishing semen fertilizing ability. The main aim of the study was to verify the applicability of protein carbonyl derivatives measurement in the SP of canine and stallion, using a method with 2,4-dinitrophenylhydrazine (DNPH). The research material consisted of ejaculates obtained from eight English Springer Spaniels, and from seven half-blood stallions during the breeding and non-breeding season. The content of carbonyl groups in the SP was measured on the basis of the reactions with DNPH. The following reagent variants were used to dissolve protein precipitates: Variant 1 (V1) - 6M Guanidine solution and Variant 2 (V2) - 0.1M NaOH solution. It has been shown that to obtain reliable results for the measurement of protein carbonylated groups in the dog and horse SP, both 6M Guanidine and 0.1M NaOH may be used. A correlation was also found between the number of carbonyl groups and the total protein content in the canine (V1: r = -0.724; V2: r = -0.847) and stallion (V1: r = -0.336; V2: r = -0.334) SP. Additionally, the study showed a higher content (p≤0.05) of protein carbonyl groups in the stallion SP in the non-breeding season compared to the breeding season. The method based on the reaction with DNPH, due to its simplicity and cost effectiveness, appears to be suitable for large-scale application in the determination of the SP proteins oxidative damage in dog and horse semen.

Assessment of bacterial pollution of closed water supply systems of galvanized productions

This work is devoted to assessment of the bacterial contamination of drainage systems in a galvanic production. In the course of the study, two strains of microorganisms which cause microbial contamination and lead to a decrease in the efficiency of the process equipment were isolated from water and wash sediment samples taken in the industrial water supply system of the enterprise and identified. Our study of the morphological and cultural properties of the isolated strains of bacteria has allowed them to be attributed to the genus Bacillus. As a result of a metagenomic analysis of the composition of microbial communities for the 16S rRNA gene (16S rDNA variable regions) according to the GenBank database on an ABI Prism 3730 automatic sequencer, the homology of the first strain with typical strains of the subgroup B. velezensis and B. amyloliquefaciens was established within 99.4–99.9%. When identifying the second isolated strain, the homology with B. altitudinis was 99.7%. Our study of the properties of the isolated strains has shown that they are neither pathogenic nor toxigenic. To reduce the microbial load in the technical water supply system, a series of experiments was carried out to select a biocide. Several variants of disinfectants of various groups were tested, namely: oxidizing ones (chloramine (a chlorine derivative of ammonia), hydrogen peroxide) and non-oxidizing ones (polymeric derivatives of polyhexamethylene guanidine (PHMG) produced by JSC NPK Mediana-filter and polyazolidine ammonium ionohydrate (PAG-M) produced by LLC “Constanta”). The polymeric compounds were found to be more effective than the chlorine-based disinfectants. An aqueous solution of polyhexamethylene guanidine had the best bactericidal effect on the microorganisms, therefore it was recommended to combat the existing bacterial contamination.

ASSESSMENT OF THE INTESTINAL MICROBIOTA IN ADULTS WITH EROSIVE ESOPHAGITIS.

The intestinal microbiota influences the appropriate function of the gastrointestinal tract. Intestinal dysbiosis may be associated with a higher risk of esophageal lesions, mainly due to changes in gastroesophageal motility patterns, elevation of intra-abdominal pressure, and increased frequency of transient relaxation of the lower esophageal sphincter. The aim of this study was to evaluate the intestinal microbiota in individuals with erosive esophagitis and in healthy individuals using metagenomics. A total of 22 fecal samples from adults aged between 18 and 60 years were included. Eleven individuals had esophagitis (eight men and three women) and 11 were healthy controls (10 men and one woman). The individuals were instructed to collect and store fecal material into a tube containing guanidine solution. The DNA of the microbiota was extracted from each fecal samples and PCR amplification was performed using primers for the V4 region of the 16S rRNA gene. The amplicons were sequenced using the Ion Torrent PGM platform and the data were analyzed using the QIIME™ software version 1.8. Statistical analyses were performed using the Mann-Whitney non-parametric test and the ANOSIM non-parametric method based on distance matrix. The alpha-diversity and beta-diversity indices were similar between the two groups, without statistically significant differences. There was no statistically significant difference in the phylum level. However, a statistically significant difference was observed in the abundance of the family Clostridiaceae (0.3% vs 2.0%, P=0.032) and in the genus Faecaliumbacterium (10.5% vs 4.5%, P=0.045) between healthy controls and esophagitis patients. The findings suggest that reduced abundance of the genus Faecaliumbacterium and greater abundance of the family Clostridiaceae may be risk factors for the development of erosive esophagitis. Intervention in the composition of the intestinal microbiota should be considered as an adjunct to current therapeutic strategies for this clinical condition.

Guanidine solution as a new fungicidal for heat-polymerized acrylic resins

Guanidine solution as a new fungicidal for heat-polymerized acrylic resins

Carboxylic acid functionalized ortho-linked oxacalix[2]benzene[2]pyrazine: synthesis, structure, hydrogen bond and metal directed self-assembly

Cyclooligomerization of 2,6-dichloropyrazine 4 and benzyl 2,3-dihydroxybenzoate 5 under microwave irradiation resulted in a racemic pair of ester functionalized ortho-linked oxacalix[2]benzene[2]pyrazine 6, which was further transformed to the corresponding racemic carboxylic acid functionalized ortho-linked oxacalix[2]benzene[2]pyrazine 3. Both enantiomers of 3 adopt 1,3-alternate conformations with their two carboxylic acid groups pointing to opposite directions in the solid state. Enantiomers of 3 form a step-like one-dimensional supramolecular polymer via intermolecular hydrogen bond interactions between the carboxylic acids for crystals obtained in methanol. No hydrogen bonds were formed between the carboxylic acids for crystals of 3 obtained in pyridine and aqueous guanidine solutions; instead, intermolecular hydrogen bonds between the carboxylic acid groups of 3 and pyridine, as well as guanidinium ions were formed. Under metal-mediated self-assembly conditions, the pyrazinyl nitrogen atoms in 3 interacted with transition metal ions, such as Ag(I), Cu(II) and Zn(II), and resulted in the formation of four new metal-containing supramolecular complexes. Metallomacrocycles 7, 8 and 9 were formed by reactions of 3 with Ag(I) or Cu(II) ions by bridging two ligands 3 in the equatorial region via M-N coordination bonds. A one-dimensional coordination polymer 10 was generated by reaction between ligand 3 and Zn(II) ions, and a cage-based structure is presented in 10 by bridging of the cyclophane units by Zn(2+) ions via Zn-N and Zn-O bonds.

Reagent treatments of sediments built up in sedimentation tanks of the Dnieper river water station

Laboratory experiments, modeling compaction of sediments building up in sedimentation tanks of water stations under the influence of a GKZh-11 hydrophobizing liquid, the solution of polyhexamethylene guanidine (Aquaton), aluminum sulfate, were carried out. We have determined optimal doses of reagents. It has been shown that the greatest effect of compacting of sediments (21–23%) is achieved by the use of a GKZh-11 hydrophobizing agent and also with a joint action of the hydrophobizing agent and aluminum sulfate (13–18%). The obtained data present a practical interest when developing the technology of treating sediments of washing waters of the sedimentation tanks and filters of water-treatment facilities.

The impact of low-molecular amines on the extraction of nitrates by the nanofiltration method

The paper has investigated extraction of nitrate ions from aqueous solutions by a OPMN-P membrane in the presence of low-molecular amines of guanidine and urotropine. It showed the impact of the pH and the concentration of nitrate ions on this process. It has been found that the presence in the solution of guanidine results in a decrease of the degree of retention of nitrates by the membrane two- or threefold compared with the solutions not containing this amine, while the presence of urotropine in the neutral and acid regions of the pH in the equimolar ratio to nitrate ions makes it possible to raise the retention degree of the latter by 10%.

Reversible Performance of Dodecyl Tetramethyl Guanidine Solution Induced by CO2Trigger

AbstractDodecyl tetramethyl guanidine (DTMG) were synthesized and characterized, and its reversible performance was studied. The results showed that DTMG could form bicarbonate ionic adduct after exposed to CO2, so it could be used as CO2switchable surfactants. By bubbling CO2through DTMG solution or heating CO2saturated DTMG solution, the alkali and surface active properties of solution was changed reversibly. Emulsion and foam stabilized by DTMG could be controlled between stable and unstable state by CO2. In addition, the state of DTMG solution was easy to be distinguished by naked eye through a simple indicator, phenolphthalein. Pink indicated it was inactive, and colorless indicated it was active.

Complete reactivation of immobilized derivatives of a trimeric glutamate dehydrogenase from Thermus thermophillus

First, the enzyme immobilized on cyanide bromide agarose beads (CNBr) (that did not involve all enzyme subunits in the immobilization) has been crosslinked with aldehyde-dextran. This preparation did not any longer release enzyme subunits and become fully stable at pH 4 and 25 °C. Then, the stabilities of many different enzyme preparations (enzyme immobilized on CNBr, that derivative further crosslinked with aldehyde-dextran, enzyme immobilized on highly activated amino-epoxy supports, GDH immobilized on supports having a few animo groups and many epoxy groups, GDH immobilized on glyoxyl-agarose beads at pH 7, and that preparation further incubated at pH 10, and finally the enzyme immobilized on this support directly at pH 10) were compared at pH 4 and high temperatures, conditions where both dissociation and distortion play a relevant role in the enzyme inactivation. The most stable preparation was that prepared at pH 7 and incubated at pH 10, followed by GDH immobilized on amino and epoxy supports and the third one was the enzyme immobilized on glyoxyl-agarose at pH 10. The incubation of all enzyme preparations in saturated guanidine solutions produced the full inactivation of all enzyme preparations. When not all enzyme subunits were immobilized, activity was not recovered at all. Among the other derivatives, only glyoxyl preparations (the most inert supports and those where a more intense multipoint covalent attachment were expected) gave significant reactivation when re-incubated in aqueous medium. After optimization of the reactivation conditions, the enzyme immobilized at pH 7 and later incubated at pH 10 recovered 100% of the enzyme activity.

Reactivation of covalently immobilized lipase from Thermomyces lanuginosus

Lipase from Thermomyces lanuginosus (TLL) immobilized on cyanogen bromide agarose (CNBr) may be fully inactivated when incubated in saturated solutions of guanidine. When this inactivated enzyme is re-incubated in aqueous medium, 20% of the activity may be recovered for several cycles. However, if the activity was determined in the presence of a detergent (CTAB, an activator of this enzyme), 100% of the initial activity in the presence of detergent was recovered. The enzyme was also inactivated in the presence of organic solvents and at high temperatures. Inactivations were more rapid when the activity was determined in absence of detergent. In both cases, some activity could be recovered just by incubation under mild conditions, and this increase was higher if the activity measurements were performed in the presence of CTAB. These results suggested that the opening of the lipase could be a critical step in the inactivation or reactivation of immobilized TLL. In inactivations in the presence of solvents, 100% of activity could be recovered during several cycles, while in thermal inactivations, the recovered activity decreased in each inactivation–reactivation cycle. The incubation of the enzyme inactivated by temperature in guanidine improved the results, but still 100% could not be achieved during several cycles even measured in the presence of CTAB. Thus, the simple incubation of the partially or fully inactivated enzyme under mild conditions permitted to recover some activity (enhancing the half life of the biocatalysts), even in thermal inactivations.

Complex assessment of toxicity, cyto-, and gentotoxicity of polyexamethyl guanidine concurrently with the use of plant and animal test-organisms and their cells

The paper presents the biotesting results of aqueous solutions of polyhexamethyl guanidine of grade Aquaton with a goal of investigating the impact of toxic, genotoxic, and cytotoxic influence of the compounds of the guanidine series on plant and animal test-organisms and their cells, i.e., assessments of their ecological safety. The given compound prepared on model and natural waters at the concentration 0.01 and 0.1 mg/dm3 causes toxic and genotoxic effects in animal and plant biotests and cellular biomakers. The concentration 0.01 mg/dm3 was an ecological safety boundary. The proposed complex approach concurrently using batteries of animal and plant test-organisms and their cells is an effective instrument for conducting a comprehensive analysis of recommended working and residual concentration of newly developed coagulants and flocculants.

Peptidomic analysis of human acquired enamel pellicle

Human acquired enamel pellicle is the result of a selective interaction of salivary proteins and peptides with the tooth surface. In the present work, the characterization of the peptides as well as the type of interactions established with the enamel surface was performed. Peptides from in vivo bovine enamel implants in the human oral cavity were sequentially extracted using guanidine and trifluoroacetic acid solutions and the fractions obtained were analysed by LC-MS and LC-MS/MS. Based on the LC-MS data, six phosphorylated peptides were identified in an intact form, strongly adsorbed to the enamel surface. Data from the LC-MS/MS analyses allowed us to identified 30 fragment peptides non-covalently bonded to enamel [basic proline-rich proteins, histatins (1 and 3) and acidic proline-rich protein classes]. The tandem mass spectrometry experiments showed the existence of a pattern of amide bond cleavage for the different identified peptide classes suggesting a selective proteolytic activity. For histatins, a predominance of cleavage at Arg, Lys and His residues was observed, while for basic proline-rich proteins, cleavage at Arg and Pro residues prevailed. In the case of acidic proline-rich proteins, a clearly predominance of cleavage of the Gln-Gly amide bond was evident.

Osteoblast Responsiveness to 1α,25‐Dihydroxyvitamin D3 during Spaceflight

Rat osteoblasts were cultured aboard a space shuttle for 4 and 5 days. Cells were treated with 1 nM 1alpha,25-dihydroxyvitamin D(3) (VD) for the last 1 day. The conditioned media were harvested. Cells were solubilized with guanidine solution on board. We examined microgravity effects on the production/expression of osteocalcin, bone sialoprotein (BSP), and VD receptor (VD-R) in osteoblasts. Under VD treatment, the osteocalcin protein level was 243 +/- 117 and 1,718 +/- 534 pg/microg cellular DNA in flight cultures and ground controls, respectively. Without VD treatment, the osteocalcin protein level was not different between flight cultures and ground controls. The osteocalcin mRNA level in the VD-treated flight cultures was as low as 16% of that in ground controls. The VD-R mRNA level in the VD-treated flight cultures was also decreased to 16% of that in ground controls. Microgravity would suppress the VD-inducible production of osteocalcin but not the basal productivity. The BSP mRNA level was increased by microgravity. VD/VD-R binds to the vitamin D-responsive element (VDRE) on the target genes. The rat osteocalcin gene is positively regulated via "enhancer" VDRE, whereas the rat BSP gene is negatively regulated via "repressor " VDRE. Microgravity might modulate osteoblast responsiveness to VD through the suppression of VD-R.

Analysis of salivary peptides using HPLC-electrospray mass spectrometry.

Salivary peptides are involved in a wide range of functions constituting the first line of defence of oral cavity and precursors of dental pellicle formation. The presence of mucins in saliva makes difficult the analysis of the proteic content. This is due mainly to aggregation phenomenon between mucins and other high molecular weight glycoproteins and salivary proteins. Considering the importance of salivary peptides in biological functions, we have evaluated the influence of four different extraction methodologies on the separation and identification of these proteins by HPLC-MS. Based on their molecular weight, we identified a total of 22 peptides when extraction was performed using a solution of guanidine (6 m), compared with 14 peptides identified when saliva is acidified with TFA, which is an often used procedure. Our results also show the presence of mucin bind peptides, which include statherin, PRP1, PRP3, Histatin 1 and Histatin 5.

Inhibition of HSP70 and a collagen-specific molecular chaperone (HSP47) expression in rat osteoblasts by microgravity.

Rat osteoblasts were cultured aboard a space shuttle for 4 or 5 days. Cells were exposed to 1alpha, 25 dihydroxyvitamin D(3) during the last 20 h and then solubilized by guanidine solution. The mRNA levels for molecular chaperones were analyzed by semi-quantitative RT-PCR. ELISA was used to quantify TGF-beta1 in the conditioned medium. The HSP70 mRNA levels in the flight cultures were almost completely suppressed, as compared to the ground (1 x g) controls. The inducible HSP70 is known as the major heat shock protein that prevents stress-induced apoptosis. The mean mRNA levels for the constitutive HSC73 in the flight cultures were reduced to 69%, approximately 60% of the ground controls. HSC73 is reported to prevent the pathological state that is induced by disruption of microtubule network. The mean HSP47 mRNA levels in the flight cultures were decreased to 50% and 19% of the ground controls on the 4th and 5th days. Concomitantly, the concentration of TGF-beta1 in the conditioned medium of the flight cultures was reduced to 37% and 19% of the ground controls on the 4th and 5th days. HSP47 is the collagen-specific molecular chaperone that controls collagen processing and quality and is regulated by TGF-beta1. Microgravity differentially modulated the expression of molecular chaperones in osteoblasts, which might be involved in induction and/or prevention of osteopenia in space.

The unfolding intermediate state of calf intestinal alkaline phosphatase during denaturation in guanidine solutions.

The equilibrium unfolding of calf intestinal alkaline phosphatase in guanidinium chloride (GdmCl) solutions was studied by following the fluorescence and ultraviolet difference spectra. At low concentrations of GdmCl (< 1.6 M), the fluorescence intensity decreased with a slight red shift of the emission maximum from 332 nm to 344 nm. An unfolding intermediate state was observed at a broad concentration range of GdmCl as a denaturant (between 1.6 and 2.6 M). This intermediate was characterized by increased fluorescence emission intensity, ultraviolet difference absorption at 236 nm and 260 nm, as well as increased binding to the protein and red shift of the fluorescence probe 1-anilinonaphthalene-8-sulfonic acid.

Room-temperature hybridization of target DNA with microarrays in concentrated solutions of guanidine thiocyanate.

BioTechniquesVol. 34, No. 6 BenchmarkOpen AccessRoom-Temperature Hybridization of Target DNA with Microarrays in Concentrated Solutions of Guanidine ThiocyanateS.-C. Tao, Y. Li, Y.-H. Liu, X.-M. Ma & J. ChengS.-C. TaoTsinghua UniversityNational Engineering Research Center for Beijing Biochip Technology, Beijing, ChinaSearch for more papers by this author, Y. LiTsinghua UniversityNational Engineering Research Center for Beijing Biochip Technology, Beijing, ChinaSearch for more papers by this author, Y.-H. LiuNational Engineering Research Center for Beijing Biochip Technology, Beijing, ChinaSearch for more papers by this author, X.-M. MaNational Engineering Research Center for Beijing Biochip Technology, Beijing, ChinaSearch for more papers by this author & J. Cheng*Address correspondence to: Dr. Jing Cheng,National Engineering Research Center for Beijing Biochip Technology (NERCBBT), Jia 2# Qinghua West Road, Haidian District, Beijing 100084, China. e-mail: E-mail Address: jcheng@tsinghua.edu.cnTsinghua UniversityNational Engineering Research Center for Beijing Biochip Technology, Beijing, ChinaSearch for more papers by this authorPublished Online:24 Sep 2018https://doi.org/10.2144/03346mt01AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInReddit "Room-Temperature Hybridization of Target DNA with Microarrays in Concentrated Solutions of Guanidine Thiocyanate." , 34(6), pp. 1260–1262FiguresReferencesRelatedDetailsCited ByProficiency Testing of Epidermal Growth Factor Receptor Mutations Detection in Saliva Using Spectrum Saliva Collector (SDNA-1000) and Preservative Solution Detected by Electric Field-Induced Release and MeasurementBiopreservation and Biobanking, Vol. 20, No. 5Development of a Linker-Mediated Immunoassay Using Chemically Transitioned Nanosensors7 February 2020 | Analytical Chemistry, Vol. 92, No. 5Progress Towards a Real-time PCR Assay for the Simultaneous Detection of Clavibacter michiganensis subsp. michiganensis and Pepino mosaic virus in Tomato Seed28 April 2012 | Journal of Phytopathology, Vol. 160, No. 7-8Determination for Enterobacter cloacae based on a europium ternary complex labeled DNA probeSpectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 82, No. 1The design and application of DNA chips for early detection of SARS-CoV from clinical samplesJournal of Clinical Virology, Vol. 33, No. 2Integrated microsystem for dielectrophoretic cell concentration and genetic detectionLab on a Chip, Vol. 5, No. 10Current Awareness on Comparative and Functional GenomicsComparative and Functional Genomics, Vol. 4, No. 6 Vol. 34, No. 6 Follow us on social media for the latest updates Metrics Downloaded 354 times History Published online 24 September 2018 Published in print June 2003 Information© 2018 Author(s)PDF download

Expression in Escherichia coli and purification of the functional feline granulocyte colony-stimulating factor

Feline granulocyte colony-stimulating factor (G-CSF) with an N-terminal histidine hexamer tag was expressed as inclusion bodies in E. coli. The G-CSF solubilized in 6 M guanidine solution was absorbed onto a Ni-NTA column and, after washing with decreasing concentrations of guanidine, eluted with imidazole in a soluble and apparently pure form. The activity of the recombinant feline G-CSF was 3×10 6 U/mg protein, as assayed by its stimulatory effect on NFS-60 cell proliferation. When a low level of purified feline G-CSF was administered once a day for two successive days to cats, the number of neutrophil increased 4-fold while the levels of other blood cell types remained virtually unchanged. Daily administration of G-CSF for a total of 11 days led to a more than 10-fold increase in neutrophils, an 8-fold increase in the number of monocytes and 2-fold increase in lymphocytes. No severe side effects or antibody production was observed in cats after administration of G-CSF.

6-Guanidinopurine nucleosides and their analogues

A general synthetic approach to 6-guanidinopurines, their ribonucleosides, 2-deoxyribonucleosides, acyclic nucleoside analogues and acyclic nucleoside phosphonates was developed. The approach consists in the reaction of the 6-chloropurine derivatives with guanidine solution in DMF under DABCO catalysis. This method was used to synthesize 6-guanidinopurine and 2-amino-6-guanidinopurine derivatives. Acyclic nucleosides and acyclic nucleoside phosphonates were also obtained by alkylation of the 6-guanidinopurine bases.