Decomposition Of Glycine Research Articles

Arbuscular mycorrhizal fungi influence decomposition of, but not plant nutrient capture from, glycine patches in soil.

• The contribution of different arbuscular mycorrhizal fungi (AMF) to nutrient capture from an organic patch, and the subsequent impact on root proliferation was investigated. • Organic patches were created with glycine labelled with 15 N and 13 C. This allowed decomposition (as 13 CO2 release) and uptake of nutrients (as 13 C and 15 N enrichments in the plant tissues) to be followed. Changes in root responses were followed in situ by the use of minirhizotrons and compared to responses in control (H2 O) patches. • Although there were differences in internal colonization and external mycelium production among the three AMF tested, none of the fungi responded to the presence of the glycine patch, and N and C capture was no different to uncolonized controls. However, the presence of glycine affected the manner in which colonized roots responded, particularly below the patch. The presence of AMF affected the decomposition of glycine. • Root responses to the presence of N-rich patches appear more important than AMF responses.

Ozone and hydroxyl radicals induced oxidation of glycine

The study of the oxidation of glycine by ozone and hydroxyl radicals has been undertaken. Different experimental procedures involving the H 2O 2/UV process or ozone in the presence of hydrogen peroxide on one hand, and ozone alone on the other hand allowed to distinguish between the two oxidation pathways. It has been shown that nitrites and nitrates are observed byproducts resulting from molecular ozonation whereas ammonium ions constitute the only inorganic nitrogen species from hydroxyl radicals induced decomposition of glycine. Therefore, the ozonation process promoting radical pathways will favor ammonia production vs. nitrates. Among the organic compounds resulting from oxidation by hydroxyl radicals, oxalic acid was the major byproduct detected in the presence of oxygen. Oxamic acid and formic acid were also observed. In addition, the nitrogen mass balance indicated the formation of unidentified nitrogen byproducts derived from glycine. These nitrogen compounds could result from the interaction of oxygen with nitrogen radical, but, mainly, with α-amino radical of glycine. This reaction is very different from the molecular ozonation which directs the attack on the nitrogen functional group before the C–N bond cleavage of the amino acid molecule.

Glycine Adsorption on Pt(111) in the Monolayer and Multilayer Regime

Glycine (GL) overlayers of varying thickness were deposited in situ on the clean Pt(111) surface by evaporating commercially available glycine powder. The temperature-stabilized evaporation source, made of Cu, was kept at 420 K during evaporation. The distance between Pt and the evaporation source was about 240 mm. The deposition rate and the total amount of glycine deposited were monitored by a quartz crystal microbalance that could be moved to intersect the GL beam approximately 40 mm downstream compared to the Pt position. The total amount of glycine in the reproduced spectra was 34 (~0.5 ML) and 340 ng/cm2 (~ 5 ML), respectively. We discuss the spectra with reference to both the neutral and zwitterionic states. There are two glycine-related C 1s peaks at both low and high GL coverages and a shoulder at ~ 285 eV most probably due to partial decomposition of glycine inside the evaporation source, at least for a thicker GL layer. The C 1s peak at lower binding energy is usually attributed to the C 1s carbon, while the peak at higher BE is supposed to stem from the carboxyl group. The energy of the peaks shifts with coverage, mainly due to the differences in charge transfer between Pt-GL (low coverage) compared to the GL-GL (high coverage). Slight charging of the sample (3.7 meV/ML) takes place, but results in a virtually uniform shift of all the GL levels involved. In the N 1s spectral region there appear two different N 1s components. The intensity of the peak at lower BE levels off with increased coverage from ~25% of the total N 1s intensity at low coverage to ~8% at higher coverages. The energy position of this lower BE peak is characteristic of NH2-like bonding. The position of the second N 1s peak suggests NH3+-like bonds. At high GL coverages the N 1s peak at low BE, and a C 1s shoulder at 285 eV, stem mainly from a slight decomposition of GL inside the evaporation source (below 8%). At low glycine coverages (<1 ML) there exist two different GL states on the surface: a majority of the amino acid molecules form zwitterions, while the remaining part is either neutral or decomposes into fragments some of which contain the NH2 group.

Selective decomposition of either enantiomer or aspartic acid irradiated with60Co-γ-rays in the mixed aqueous solution with D- or L-alanine

Aqueous solutions of various amino acids were irradiated with60Co-γ-rays, and subsequently the remaining amino acids were analyzed using HPLC. The D37 for the 1 mM glycine and alanine solutions were 1.95×104 and 1.48×104 Gy, respectively. However, when the mixed solutions of glycine and alanine (each in 0.5 mM) were irradiated under the identical condition, the D37 for the glycine decomposition increased to 3.56×104 Gy, while that for alanine decreased to 0.65×104 Gy. A similar phenomenon was observed also in the case of the mixed solutions of aspartic acid and alanine. Namely, aspartic acid was protected from the attack of radiation by the presence of alanine in the solutions. The most interesting finding in this combination experiment is that, when D,L-aspartic acid was irradiated in the presence of L-alanine, the radiation-sensitivity of L-aspartic acid decreased selectively and vice versa. Namely, the asymmetric field induced in the solutions by adding D- or L-alanine might affect the radiodecomposition rate of either aspartic acid. Addition of glycine to D,L-aspartic acid did not bring about the asymmetric decomposition. It seems that some interaction between these amino acid molecules resulted in this effect.

Molecular Beam Studies of Thermal Decomposition of Glycine on Solid Surfaces

A molecular beam technique for studying the decomposition of vapor-phase glycine on solid surfaces has been developed. The decomposition probability of glycine on the surfaces of polycrystalline molybdenum oxide and glass was measured as a function of the surface temperature. Decomposition products were quantitatively analyzed with a mass spectrometer in the temperature range of 420–800 K. The probability of decomposition of glycine per one collision with molybdenum oxide was found to be almost unity at a high surface temperature (∼800 K), while that with glass was less than 0.15 in the observed temperature range. The values of activation energy E and the pre-exponential factor SZ2/Z1 for the decomposition are determined. A new model based on the transition state theory to evaluate the values of the pre-exponential factor is proposed.

Radiation chemistry of an aqueous solution of glycine: compounds of interest to chemical evolution studies.

We have examined the radiolysis of an O2-free aqueous solution of glycine at absorbed doses of 60Co gamma-radiation of up to 20 Mrad. At least 20 compounds are formed during radiolysis, among them several amino acids, an oligoamine, and the nitrogen-free polymers (Mw less than or equal to 28,000 daltons). When dicyandiamide is present in the solution of glycine, various nitrogen-containing products, including some polymers (Mw less than or equal to 12,000 daltons), are synthesized along with radiolytic products of glycine; polyglycines are not formed. We have determined the radiation-chemical yields of radiolytic-product formation and of decomposition of glycine, and have considered possible free-radical reactions leading to the radiation-induced changes observed.

The Reaction of Hypochlorite with Glycine. I. Decomposition of Glycine and Formation of Cyanogen Chloride

In the reaction of hypochlorite with amino acids, chloramine is formed at the first stage, and then decarboxylation and oxidation occur. Thus, either corresponding aldehyde and ammonia or corresponding nitrile is formed from amino acids. In the present studies, the products in the reaction mixture of glycine with hypochlorite at neutral condition are determined quantitatively. When the molar ratio of hypochlorite to glycine was less than 1, the residual chlorine and glycine were stable in the reaction mixture ; thus no ammonia and no aldehyde were formed. At the molar ratio ranging from 1 to 3, cyanide and cyanogen chloride were produced. Maximum formation of cyanide was observed at the ratio of about 2, but its yield was only 20% of glycine. When hypochlorite reacted on glycine at the molar ratio of 3, cyanogen chloride was produced in a quantitative yield. Cyanogen chloride was degraded by subsequent addition of excess hypochlorite. From these results, it is concluded that the nitrile formation is a main reaction of glycine with hypochlorite.

Studies on the Formation of Abnormal Substances in Foods by Treatment with Hydrogen Peroxide (II)

Identification of the Escherichia coli K-12 (E. coli) inhibiting substance formed by the decomposition of glycine with hydrogen peroxide (H2O2) or bleaching of foods with H2O2 were studied.The inhibition substance zone appeared at Rf 0.2-0.4 on the bioautogram (n-butanol: acetic acid: water=60: 15: 25) of glycine oxidation products, and the substance was positive to qualitative tests of formaldehyde (Rimini test, egg albumin iron test, acetylacetone test and chromotropic acid test). Melting point, paper chromatogram, thin-layer chromatogram and infrared spectrum of yellow crystal obtained with the addition of acetylacetone reagent to the extracts from the zone of Rf 0.2-0.4 on the paper chromatogram were coincident with those of 3, 5-diacetyl-1, 4-dihydrolutidine (DDL).Since E. coli inhibiting substance in the glycine oxidation products was proved to be formaldehyde from the above results, it was examined on the formation of formaldehyde in foods treated with H2O2.Commercial foods containing 2-30ppm of formaldehyde were bleached with 3% hydrogen peroxide under the following conditions (10g of the samples were treated with 50ml of 3% H2O2, and kept at 50°C for 1 hour). Formaldehyde was produced in these samples at the level of 16-34ppm, while its concentration in soaking solutions was within the range of 10-68ppm. Further, the amounts of formaldehyde were determined after standing at room temperature for a week, and 40-68ppm of formaldehyde was found in the foods. In case distilled water was used as soaking solution, no increase in formaldehyde content was observed.

Formation of Amino-acids by Thermal Decomposition of Formamide—Oligomerization of Hydrogen Cyanide

Heyns and Pavel1 reported on the pyrolytic decomposition of glycine in which small amounts ot other amino-acids (alanine, aspartic acid, α-aminobutyric acid) and other carboxylic acids (fumaric acid, oxalic acid, succinic acid) were found. The formation of hydrogen cyanide was also confirmed in the reaction mixture.

CONTINUOUS FLOW METHOD IN SOIL MICROBIOLOGY. IV. DECOMPOSITION OF GLYCINE.

CONTINUOUS FLOW METHOD IN SOIL MICROBIOLOGY. IV. DECOMPOSITION OF GLYCINE.