Addition Of Glycine Research Articles

Single crystal growth and enhancing effect of glycine on characteristic properties of bis-thiourea zinc acetate crystal

A single crystal of glycine-doped bis-thiourea zinc acetate (G-BTZA) with a dimension of 15 × 6 × 4 mm3 has been grown using the slow solution evaporation technique. The structural parameters of the crystals were determined using the single crystal XRD technique. The increase in optical transparency of the doped BTZA crystal was ascertained in the range of 200 to 900 nm using UV–visible spectral analysis. The improved optical band gap of the G-BTZA crystal is found to be 4.19 eV, and vital optical constants have been calculated using the transmittance data. The influence of glycine on the mechanical parameters of the BTZA crystal has been investigated via microhardness studies. The thermal stability of pure and doped BTZA crystals has been determined by employing the thermogravimetric and differential thermal analysis technique. The improvement in the dielectric properties of the BTZA crystal after the addition of glycine has been evaluated in a temperature range of 30 to 120 °C at a frequency of 100 KHz. The SHG efficiency of the glycine-doped BTZA crystal is found to be much higher than KDP and BTZA crystal material in a Kurtz–Perry powder analysis.

Influence of Soluble Fillers in Improving Porosity of Handmade Antibiotic-Impregnated Polymethyl Methacrylate (PMMA) Beads: An in-vitro Study.

There have been many investigations on non-biodegradable materials acting as an antibiotic carrier for local drug delivery systems based on polymethyl methacrylate (PMMA) beads. However, the material is non-degradable and non-porous so that less than 5% of the encapsulated drug is released. In order to obtain better release of the antibiotics, greater porosity of the beads would be required. Adding fillers could increase the bead’s porosity, thus improving the antibiotic release from the beads. The purpose of the study is to optimize release kinetics of gentamicin from handmade beads by adding fillers such as glycine and sodium chloride in different concentrations. Terms of percolation theory will qualitatively be applied in interpreting the final results. Model beads were made by blending the antibiotics (gentamicin) with powdered PMMA, prepared with the inclusion of glycine and different concentration of sodium chloride in 100% monomer. To determine the gentamicin release, beads were placed in phosphate buffered saline (PBS) and aliquots were taken at designated times to measure the gentamicin concentration. Addition of glycine yielded 16 % release of the total amount of gentamicin incorporated in 24 hours. Subsequent addition of sodium chloride resulted in an increased gentamicin release, with little or no difference in gentamicin release once 16 g or more sodium chloride was added (gentamicin release 100% of the amount incorporated). In conclusion, addition of glycine and sodium chloride resulted in an increased release of gentamicin; however, the combination without sodium chloride seemed to have an inhibitory effect on the gentamicin release.

Improved extracellular expression and high-cell-density fed-batch fermentation of chitosanase from Aspergillus Fumigatus in Escherichia coli.

Chitosanase (CSN) from Aspergillus fumigatus has good thermal stability, wide pH range duration, and effective hydrolysis for chitosan. Inhere, CSN was successfully expressed in Escherichia coli followed by extracellular secretion under the guidance of an N-terminal signal peptide PelB, which effectively prompted its secretion out of E. coli cells. To facilitate its later purification, N-terminal or C-terminal 6xHis epitope tag was added to the PelB-CSN protein complex. Our results indicated that PelB-CSN without 6xHis-tag (PelB-CSN) or with N-terminal 6xHis-tag (PelB-CSN-N) can both be effectively secreted into the medium, while CSN with 6xHis-tag anchored at C-terminus was expressed as inclusion bodies. Process optimization strategies were further developed to improve the secretion efficiency of recombinant PelB-CSN-N in E. coli. Under the induction of 10g/L lactose in shake-flask culture, the extracellular activity of CSN reached 6015U/mL at 25°C in TB medium containing 1% glycine. Moreover, a fed-batch fermentation strategy for high-cell-density cultivation was applied in a 5-L fermenter, increasing the extracellular CSN activity to 14,000U/mL in 2-day fermentation with the optimal addition of lactose and glycine.

A simple solution for antibody signal enhancement in immunofluorescence and triple immunogold assays.

Immunolocalization techniques are standard in biomedical research. Tissue fixation with aldehydes and cell membrane permeabilization with detergents can distort the specific binding of antibodies to their high affinity epitopes. In immunofluorescence protocols, it is desirable to quench the sample's autofluorescence without reduction of the antibody-dependent signal. Here we show that adding glycine to the blocking buffer and diluting the antibodies in a phosphate saline solution containing glycine, Triton X-100, Tween20 and hydrogen peroxide increase the specific antibody signal in tissue immunofluorescence and immunogold electron microscopy. This defined antibody signal enhancer (ASE) solution gives similar results to the commercially available Pierce Immunostain Enhancer (PIE). Furthermore, prolonged tissue incubation in resin and fixative and application of ASE or PIE are described in an improved protocol for triple immunogold electron microscopy that is used to show co-localization of GABA-A ρ2 and dopamine D2 receptors in GFAP-positive astrocytes in the mouse striatum. The addition of glycine, Triton X-100, Tween20 and hydrogen peroxide during antibody incubation steps is recommended in immunohistochemistry methods.

Electrochemical detection of copper ions leached from CuO nanoparticles in saline buffers and biological media using a gold wire working electrode

We performed explorative cyclic voltammetry in phosphate-buffered saline buffers, Dulbecco’s modified Eagle’s medium (DMEM), and fetal bovine serum-added DMEM using Au wire as working electrode, both in the absence and in the presence of known nominal concentrations of Cu2+ ions or 15 nm CuO nanoparticles. Addition of either Cu2+ ions or aqueous suspension of CuO nanoparticles caused a single anodic peak to appear in the double-layer region of all three pristine media. The height of the anodic peak was found to increase in a monotonic fashion vs. Cu2+ concentration in Cu2+-added media, and versus time since CuO addition in CuO-added media. Stepwise addition of glycine to Cu2+-added phosphate-buffered saline buffer caused an increasing cathodic shift of the anodic peak accompanied by decreasing peak currents. Results indicate that preparing Cu2+-free suspensions of CuO nanoparticles in such media is difficult, owing to the presence of leached copper ions. The implications on results of experiments in which CuO nanoparticle-added biological media are used as cell culture substrates are discussed. Literature data on the interactions between Cu2+ ions, dissolved carbon dioxide in aqueous CuO suspensions, and amino acids present in such media are compared to our results.

Understanding the vapour–liquid equilibrium of CO2 in mixed solutions of potassium carbonate and potassium glycinate

A thermodynamic model was developed to describe the absorption of CO2 into a glycine promoted potassium carbonate solution. It was found that the model could effectively predict vapour–liquid equilibrium of CO2 and solubility of hydrated potassium carbonate and potassium bicarbonate in glycine promoted K2CO3 solutions over a range of temperatures. Both simulation and experimental results showed CO2 partial pressure decreased with the addition of glycine, indicating a good potential to improve CO2 absorption efficiency in potassium carbonate solution.

Effects of cadmium on the cuttlefish Sepia pharaonis’ arginine kinase: unfolding kinetics integrated with computational simulations

Arginine kinase is closely associated with adaptation to environmental stresses such as high salinity and heavy metal ion levels in marine invertebrates. In this study, the effects of Cd2+ on the cuttlefish Sepia pharaonis’ arginine kinase (SPAK) were investigated. SPAK was isolated from the muscles of S. pharaonis and upon further purification, showed a single band on SDS-PAGE. Cd2+ effectively inactivated SPAK, and the double-reciprocal kinetics indicated that Cd2+ induced non-competitive inhibition of arginine and ATP. Spectrofluorometry results showed that Cd2+ induced tertiary structure changes in SPAK with the exposure of hydrophobic surfaces that directly induced SPAK aggregation. The addition of osmolytes, glycine, and proline successfully blocked SPAK aggregation and restored the conformation and activity of SPAK. Molecular dynamics simulations involving SPAK and Cd2+ showed that Cd2+ partly blocks the entrance of ATP to the active site, and this result is consistent with the experimental results showing Cd2+-induced inactivation of SPAK. These results demonstrate the effect of Cd2+ on SPAK enzymatic function and unfolding, including aggregation and the protective effects of osmolytes on SPAK folding. This study provides concrete evidence of the toxicity of Cd2+ in the context of the metabolic enzyme SPAK, and it illustrates the toxic effects of heavy metals and detoxification mechanisms in cuttlefish.

Improving the electro-transformation efficiency of Corynebacterium glutamicum by weakening its cell wall and increasing the cytoplasmic membrane fluidity.

To improve the transformation efficiency of Corynebacterium glutamicum cells with heterogenous plasmid DNA and single-strand DNA (ssDNA) using a methodology based on electro-transformation. A semicomplex hypertonic medium was selected with addition of glycine and DL-threonine to weaken cell walls and addition of Tween 80 and isonicotinic acid hydrazide to increase cytoplasmic membrane fluidity. Their contents were optimized by response surface methodology. Cell growth, electro-transformation buffer, and transformation protocol were also optimized. Temporary heating inactivation of the host restriction enzyme showed a significant effect. Finally, a high transformation efficiency of 3.57±0.13×10(7)cfu/μg DNA of plasmid and 1.05×10(6)Str (R) cfu per 10(9) viable cells with a ssDNA was achieved. The results shed light on the application in functional genomics and genome editing of C. glutamicum.

Effects of various amino acids as organic nitrogen sources on the growth and biochemical composition of Chlorella pyrenoidosa

This study investigated the effects of eighteen l-amino acids on the growth and biochemical composition of Chlorella pyrenoidosa. Under the nitrate deficiency condition, ten l-amino acids were found to exert stronger stimulative effects on the algal growth than the other amino acids. After 10-day culture, addition of 0.5gL−1 the above mentioned ten amino acids significantly increased the cellular protein contents by 441.3–110.8%, respectively, and significantly decreased the carbohydrate contents by 60.7–16.2%, respectively. Under the normal nitrate condition, the cellular biochemical composition was not significantly affected by addition of serine, leucine, proline, aspartic acid, asparagine, and glycine, whereas addition of aspartic acid and arginine increased the algal biomass by 110.2% and 62.8% compared with the control. Finally, the significance of this work in the biotechnological application of culturing C. pyrenoidosa in organic wastewater rich in amino acids was further discussed.

Warming decreased and grazing increased plant uptake of amino acids in an alpine meadow.

Organic nitrogen (N) uptake by plants has been recognized as a significant component of terrestrial N cycle. Several studies indicated that plants have the ability to switch their preference between inorganic and organic forms of N in diverse environments; however, research on plant community response in organic nitrogen uptake to warming and grazing is scarce. Here, we demonstrated that organic N uptake by an alpine plant community decreased under warming with (13)C-(15)N-enriched glycine addition method. After 6years of treatment, warming decreased plant organic N uptake by 37% as compared to control treatment. Under the condition of grazing, warming reduced plant organic N uptake by 44%. Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau. Besides, soil NO 3-N content explained more than 70% of the variability observed in glycine uptake, and C:N ratio in soil dissolved organic matter remarkably increased under warming treatment. These results suggested warming promoted soil microbial activity and dissolved organic N mineralization. Grazing stimulated organic N uptake by plants, which counteracted the effect of warming.

Manipulation of lysozyme phase behavior by additives as function of conformational stability

Undesired protein aggregation in general and non-native protein aggregation in particular need to be inhibited during bio-pharmaceutical processing to ensure patient safety and to maintain product activity. In this work the potency of different additives, namely glycerol, PEG 1000, and glycine, to prevent lysozyme aggregation and selectively manipulate lysozyme phase behavior was investigated. The results revealed a strong pH dependency of the additive impact on lysozyme phase behavior, lysozyme solubility, crystal size and morphology. This work aims to link this pH dependent impact to a protein-specific parameter, the conformational stability of lysozyme. At pH 3 the addition of 10% (w/v) glycerol, 10% (w/v) PEG 1000, and 1M glycine stabilized or destabilized lysozymes’ native conformation resulting in a modified size of the crystallization area without influencing lysozyme solubility, crystal size and morphology. Addition of 1M glycine even promoted non-native aggregation at pH 3 whereas addition of PEG 1000 completely inhibited non-native aggregation. At pH 5 the addition of 10% (w/v) glycerol, 10% (w/v) PEG 1000, and 1M glycine did not influence lysozymes’ native conformation, but strongly influenced the position of the crystallization area, lysozyme solubility, crystal size and morphology. The observed pH dependent impact of the additives could be linked to a differing lysozyme conformational stability in the binary systems without additives at pH 3 and pH 5. However, in any case lysozyme phase behavior could selectively be manipulated by addition of glycerol, PEG 1000 and glycine. Furthermore, at pH 5 crystal size and morphology could selectively be manipulated.

Preparation of glycine–modified silica nanoparticles for the adsorption of malachite green dye

Organo-functionalized silica nanoparticles were prepared using an in situ modified sol–gel process (hydrolysis–esterification–condensation). This was accomplished under basic conditions by the addition of glycine as a modifier. Evidence of glycine presence was supported by Fourier Transform Infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The addition of 10 wt% glycine into the silica precursor (tetraethoxysilane), in ethanol or methanol media, resulted in a small particle size with a narrow particle size distribution and a high surface area. This is known as a mesoporous structure with a high adsorption volume. Adsorption behavior of the glycine-modified silica nanoparticles was then investigated using a malachite green (MG) dye. Adsorption capacity was raised by increasing the amount of glycine modified silica, MG concentration, and contact time. The Langmuir adsorption isotherm gave the best fit to the experimental data, suggesting monolayer adsorption on a homogenous surface. Adsorption kinetics were predicted by the pseudo-first order kinetic model rather than the pseudo-second order kinetic model, in which the values of adsorption capacity between the theoretical and experimental were more consistent.

Preparation of β-hydroxy-α-amino Acid Using Recombinant d-Threonine Aldolase

The chiral β-hydroxy-α-amino acid, (2R,3S)-2-amino-3-hydroxy-3-(pyridin-4-yl)-propanoic acid, is a key intermediate in the synthesis of the API (2R,3S)-2-amino-3-hydroxy-3-(pyridin-4-yl)-1-(pyrrolidin-1-yl)propan-1-one, a developmental drug candidate. Two d-threonine aldolase enzymes were identified to catalyze the aldol addition of glycine and pyridine 4-carboxaldehyde for the synthesis of the β-hydroxy-α-amino acid. The two d-threonine aldolase enzymes have similar properties. Efficient recombinant E. coli fermentation processes were developed for producing the enzymes. The stabilities of the enzymes were significantly improved by addition of divalent cations. An unexpected and beneficial finding was that the β-hydroxy-α-amino acid aldol addition product directly crystallized out from the reaction mixture in high purity and high diastereo- and enantioselectivity, contributing also to high yield and allowing easy isolation, processing, and downstream utilization. The temperature, pH, and amounts of reactants and enzyme were optimized to minimize reaction time and enzyme and raw material usage and maximize amino acid formation. Efficient d-threonine aldolase-catalyzed synthesis and recovery of the β-hydroxy-α-amino acid at the 100 L scale was demonstrated leading to a highly efficient and environmentally friendly process for the production of the API.

Effect of glycine addition on the structural, thermal, optical, mechanical and electrical properties of Sr (HCOO)2·2H2O crystals

Pure and glycine doped strontium formate dihydrate (SFD) single crystals were grown by the free evaporation method to understand the effect of glycine addition on the structural, thermal, optical, mechanical and electrical properties of SFD crystal. The grown crystals were characterized by carrying out powder X-ray diffraction, high resolution X-ray diffraction, Fourier transform infrared spectral, Raman spectral, UV–vis-NIR spectral, thermogravimetric (TG/DTA), second harmonic generation (SHG), microhardness and DC electrical conductivity measurements. Results obtained in the present study indicate improvement in crystalline perfection, optical transmittance, and SHG efficiency, and change in microhardness, and DC electrical conductivity on doping SFD with glycine. In addition, a large size (~1.9cm length, ~1.2cm breath and ~0.6cm height) SFD crystal with good optical quality could be grown successfully by the seeded free evaporation method.

Cryopreservation of strip spawned sperm using non-programmable freezing technique in the blue musselMytilus galloprovincialis

In this study, a non-programmable freezing technique has been developed with the strip spawned blue mussel (Mytilus galloprovincialis) sperm. The key parameters optimized including (1) cryoprotectant agents (CPAs); (2) cooling temperature; (3) thawing temperature; (4) sugar and amino acid supplementation and (5) sperm to egg ratio. The fertilization rate and/or integrity of plasma membrane and acrosome were used as sperm quality assessment indicators. The highest post-thaw sperm fertilization rate of 95% was achieved, when sperm were cryopreservated in 8% dimethyl sulfoxide at 7.8 cm above the liquid nitrogen surface and thawed in a 60°C seawater bath. The addition of glucose, sucrose or trehalose in dimethyl sulfoxide did not, whereas 0.8% glycine did significantly improve the post-thaw sperm fertilization rates. The fluorescent evaluation has demonstrated that the addition of glycine significantly improved the post-thaw sperm acrosome integrity, revealing a positive role of glycine in the improvement of post-thaw sperm quality in blue mussels.

Effect of arsenic on δ-aminolevulinic acid formation in greening maize leaf segments

Supply of 0.5 mM Na2AsO4 significantly decreased the δ-amino levulinic acid (ALA) content and total chlorophylls in greening maize leaf segments with the effect being more substantial for the later. Inclusion of precursors of chlorophyll also affected the ALA content. Thus, % decrease by arsenic (As) was significantly reduced in the presence of glutamine and MgCl2, but was increased by glycine and succinate. ALA formation and chlorophyll content were significantly decreased by 0.5 mM Na2AsO4 during levulinic acid treatment in light as well as dark with more severe effect in light. Difference in ALA accumulation in light and dark (L–D) was also substantially decreased by higher concentrations of As. Inclusion of succinate and MgCl2, respectively, increased and decreased the % inhibition of ALA formation in light. In dark the addition of 2-oxoglutaric acid (2-OG), succinate and glycine caused an increase in % inhibition of ALA formation, while glutamate caused a decrease in inhibition. Inclusion of adenosine tri phosphate (ATP) increased the ALA formation in light in presence of As only, while pyridoxal phosphate (PLP) and MgCl2 enhanced it under both conditions. The results demonstrate more prominent decrease in total chlorophylls than ALA content and/or formation in the presence of As, indicating the involvement of other steps of chlorophyll biosynthesis in addition to ALA synthesis. Substantial decrease under dark at higher concentrations of As and protective effect of cofactors, such as, MgCl2, PLP and ATP in ALA formation in light suggests that chloroplastic ALA synthesizing activity is more sensitive to the presence of As.

Gold leaching in cyanide-starved copper solutions in the presence of glycine

In the cyanidation of copper–gold ores, the presence of copper minerals can lead to soluble gold losses, the production of weak acid dissociable (WAD) cyanide, as well as a number of operational challenges in CIP/CIL circuits with regard to competitive adsorption, and subsequent difficulties associated with elution, electrowinning and smelting. In addition, copper minerals are significant cyanide consumers, leading to higher cost in ore treatment. This paper presents a process to enhance the dissolution of gold using copper–cyanide solutions in the presence of glycine where the solution is cyanide starved. The effect of glycine addition on gold leaching kinetics in copper–cyanide solutions under different leaching conditions was studied. The results show that, in the presence of glycine, gold dissolution rate increases significantly in solutions containing copper–cyanide species at a very low, or zero, free cyanide concentration. In the presence and absence of glycine, gold dissolution rates in solutions containing 10mM Cu(CN)32− were 11.1μmol/m2·s and 0.65μmol/m2·s, respectively. It is shown that the average gold dissolution rate in a Cu–CN−-glycine system is about 6.5 times higher than the gold dissolution rate in the conventional cyanidation, the presence of cyanide being similar in each system. Kinetic and electrochemical studies were conducted to evaluate the effects of glycine concentration, pH, CN/Cu ratio, and initial copper concentrations on the dissolution of gold. It has also been shown that the gold dissolution rate increases by increasing the glycine concentration up to 1g/L and any further glycine addition has a negative effect on the dissolution of gold. Increasing leaching pH up to 12 enhances gold dissolution in the copper–cyanide–glycine solutions. However, increasing leaching pH to 13 has an adverse effect on the dissolution of gold.

English

Biodegradation of acid blue 113 has been studied using two strains-Staphylococcus aureus and Escherichia coli. The effect of pH, time, initial dye concentration, the inoculum size, the co-substrate, static and shaking on decolourisation was studied. The optimum condition for decolourisation was found to be at pH 7 for an initial dye concentration of 200 mg/L at 37 C under static condition. The removal of dye by S.aureus and E.coli at optimum condition was 90% and 88% within 30 h and 42 h respectively. Addition of fructose and starch as carbon source increased the removal of colour by S.aureus and E.coli respectively. Similarly addition of ammonium formate and glycine as nitrogen source under static condition increased the colour removal by S.aureus and E. coli. The enzyme activity of azoreductase for S. aureus and E. coli was found to be 7.33 U/ml and 7.24 U/ml respectively. The COD reduction, FTIR and TLC analysis of the sample before and after decolourisation confirmed the biodegradation of dye and the formation of new metabolite. Phytotoxicity studies indicated that the microbial treated effluent is safe for disposal into the environment.

The kinetics of the inhibition of acrylamide by glycine in potato model systems.

Acrylamide (AA) is a potential carcinogen which widely exists in heat-processed foods. The addition of glycine (Gly) has been shown to reduce the formation of AA. The objective of this work was to investigate the kinetics of the inhibition of AA by Gly in both asparagine (Asn)/glucose (Glc) and Asn/Glc/Gly potato model systems during heating at 160 °C, 180 °C, and 200 °C. The simplified two consecutive first-order kinetic model fitted well to the changes of AA in both systems. No significant difference in rate constant (kF) and apparent activation energy (EaF) was observed for AA formation between the two systems (P > 0.05). Whereas EaE and only kE at 200 °C for AA elimination in the Asn/Glc/Gly system was significantly higher than Asn/Glc system (P < 0.05). The elimination reaction between Gly and AA was confirmed by the identification of their major reaction product 2-((3-amino-3-oxopropyl)amino)acetic acid in the Asn/Glc/(15) N-Gly system. The reduction of AA by Gly is predominantly attributed to the elimination reaction between Gly and AA.

The influence of excipients commonly used in freeze drying on whole blood coagulation dynamics assessed by rotational thromboelastometry.

Lyophilized reagents are used on a daily basis in coagulation diagnostics. They often contain a number of excipients in addition to the active compound. Some of these excipients may, however, influence coagulation dynamics. Besides from plasmatic coagulation bulking agents may influence platelet properties. We therefore studied the influence of a variety of bulking agents (glycine, mannitol, sucrose and trehalose) as well as a surfactant (Tween® 80) on whole blood coagulation using thromboelastometry (ROTEM®) and platelet function analysis (ROTEM® platelet). Both disaccharides as well as Tween® 80 did not influence whole blood coagulation in the concentration range investigated. The addition of glycine and mannitol solutions to the ROTEM® measurement leads to an impaired clot formation as well as overall clot strength while clotting initiation remained barely influenced. Hypertonic glycine and mannitol solutions exhibit different clot formation impairment when correlated to their osmolar concentration and compared to equally osmolar NaCl-solutions. The effect of glycine was assigned to fibrin formation impairment identified with the FIBTEM assay. Platelet function analysis revealed that hypertonic glycine solutions do not alter platelet function but hypertonic mannitol and NaCl solutions do. While the influence observed for glycine may be due to fibrinogen precipitation, the mechanism of mannitol appears to be more complex as platelet function as well as fibrin-based clot formation are influenced. This study therefore demonstrates the necessity to check for coagulation impairment due to compounds contained in lyophilized reagents.