ChemInform Abstract: CHLORAMINOMETRIC REACTIONS: KINETICS AND MECHANISMS OF OXIDATIONS OF AMINO ACIDS BY SODIUM N-CHLOROTOLUENE-P-SULFONAMIDE IN ACID AND ALKALINE MEDIA

1983 ◽  
Vol 14 (23) ◽  
Author(s):  
B. T. GOWDA ◽  
D. S. MAHADEVAPPA
Keyword(s):  
Amino Acids ◽  
Alkaline Media

scholarly journals Advances in Chemistry of Isothiocyanate-derived Colourants

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S207-S210
Author(s):  
K. Cejpek ◽  
J. Velíšek
Keyword(s):  
Amino Acids ◽  
Essential Oils ◽  
Maillard Reaction ◽  
Heterogeneous Group ◽  
Model Systems ◽  
Alkaline Media ◽  
Reaction Conditions ◽  
Condensation Products ◽  
Amino Compounds ◽  
Methylene Group

This study is focused on the reactions of isothiocyanates (ITCs) in the presence of amino compounds leading to coloured structures <I>via</I> substituted 2-thiohydantoins. A series of complementary experiments has been done and appropriate reaction conditions and structural prerequisites have been defined. Low-molecular colourants isolated and characterised from the model systems can be sorted into three groups. Yellow to red diastereomeric dehydrodimers of 2-thiohydantoin derivatives that contain an acidic methylene group are formed in mixtures consisted of ITCs and amino acids with &alpha;-methylene group in mild acidic to mild alkaline systems. The condensation products of the 2-thiohydantoins with reactive aromatic or heterocyclic carbaldehydes from the Maillard reaction, essential oils etc. comprise a heterogeneous group of mostly yellow colourants. Blue compounds of two types are structurally more complicated structures that arise from <I>N</I>-substituted amino acids and ITCs in alkaline media.

SOME FACTORS AFFECTING THE GERMINATION OF SPORES OF FOMES IGNIARIUS VAR. POPULINUS (NEUMAN) CAMPBELL, AND THE SIGNIFICANCE OF THESE FACTORS IN INFECTION

1958 ◽  
Vol 36 (3) ◽  
pp. 421-437 ◽  
Author(s):  
H. M. Good ◽  
W. Spanis
Keyword(s):  
Amino Acids ◽  
Sugar Content ◽  
Alkaline Media ◽  
Malt Extract ◽  
Factors Affecting ◽  
Extract Medium ◽  
Malt Extract Medium

Spores of F. igniarius collected from different conks at one time, or from one conk at different times of the year, varied significantly in germinability. However, spores collected from one conk within a 3-day period were judged to be sufficiently consistent for use in comparative tests.Spores germinated best on an 8% malt extract medium buffered at pH 4.0. Only a trace of germination occurred on water agar and none occurred on alkaline media. Stimulation by malt extract appeared to be due partly to the sugar content and partly to an unidentified factor.While extracts of the surface wood of aged wounds contained far less of sugars and amino acids than did extracts of fresh sapwood, germination on the former was consistently better. A lower pH appeared to account for most of this advantage but even when the two types of extract were brought to the same pH better germination occurred on the extract of the aged wound.Spores of F. igniarius germinated well at temperatures in the range 20–35 °C. They varied widely in their ability to germinate after storage. Some samples germinated fairly well after 80 days; others failed to germinate after 10 days.These findings are discussed in relation to the problems of infection.

scholarly journals Investigation of the Effect of Nanocrystalline Calcium Carbonate-Substituted Hydroxyapatite and L-Lysine and L-Arginine Surface Interactions on the Molecular Properties of Dental Biomimetic Composites

Biomimetics ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 70
Author(s):  
Dmitry Goloshchapov ◽  
Vladimir Kashkarov ◽  
Kirill Nikitkov ◽  
Pavel Seredin
Keyword(s):  
Amino Acids ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Surface Interactions ◽  
Molecular Composition ◽  
Alkaline Media ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray

Differences in the surface interactions of non-stoichiometric nanocrystalline B-type carbonate-substituted hydroxyapatite (n-cHAp) with the amino acids L-Lysine hydrochloride (L-LysHCl) and L-Arginine hydrochloride (L-ArgHCl) in acidic and alkaline media were determined using structural and spectroscopic analysis methods. The obtained data confirm that hydroxyapatite synthesized using our technique, which was used to develop the n-cHAp/L-LysHCl and n-cHAp/L-ArgHCl composites, is nanocrystalline. Studies of molecular composition of the samples by Fourier transform infrared spectroscopy under the change in the charge state of L-Lysine in environments with different alkalinity are consistent with the results of X-ray diffraction analysis, as evidenced by the redistribution of the modes’ intensities in the spectra that is correlated with the side chains, i.e., amide and carboxyl groups, of the amino acid. During the formation of a biomimetic composite containing L-Lysine hydrochloride and n-cHAp, the interaction occurred through bonding of the L-Lysine side chain and the hydroxyl groups of hydroxyapatite, which created an anionic form of L-Lysine at pH ≤ 5. In contrast, in biocomposites based on L-Arginine and n-cHAp, the interaction only slightly depends on pH value, and it proceeds by molecular orientation mechanisms. The X-ray diffraction and infrared spectroscopy results confirm that changes in the molecular composition of n-cHAp/L-ArgHCl biomimetic composites are caused by the electrostatic interaction between the L-ArgHCl molecule and the carbonate-substituted calcium hydroxyapatite. In this case, the bond formation was detected by Fourier transform infrared (FTIR) spectroscopy; the vibrational modes attributed to the main carbon chain and the guanidine group of L-Arginine are shifted during the interaction. The discovered interaction mechanisms between nanocrystalline carbonate-substituted hydroxyapatite that has physicochemical properties characteristic of the apatite in human dental enamel and specific amino acids are important for selecting the formation conditions of biomimetic composites and their integration with the natural dental tissue.

Phlyctochytrium reinboldtae (Chytridiales): morphology and physiology

1970 ◽  
Vol 48 (3) ◽  
pp. 479-484 ◽  
Author(s):  
D. J. S. Barr
Keyword(s):  
Amino Acids ◽  
Ammonium Nitrate ◽  
Pure Culture ◽  
Carbon Sources ◽  
Alkaline Media ◽  
Nitrite Nitrogen ◽  
Nitrate And Nitrite

A pure culture of Phlyctochytrium reinboldtae Persiel isolated from soil near Ottawa, Canada, grew best at 20 and 25 C, slightly at 10 C, and not at all at 35 C. It grew best in alkaline media and required no exogenous vitamins. It used ammonium, nitrate, and nitrite nitrogen and each of the 7 amino acids tested. Of 18 carbon sources, it used glucose, fructose, trehalose, maltose, mannose, cellobiose, glycerol, and starch. It is similar physiologically to P. punctatum Koch and P. plurigibbosum Barr and morphologically to P. papillatum Sparrow and P. dichotomum Umphlett.

Catalytic reduction of azlactones in alkaline media. Synthesis of amino acids

1972 ◽  
Vol 37 (18) ◽  
pp. 2916-2918 ◽  
Author(s):  
A. Badshah ◽  
Naseem H. Khan ◽  
A. R. Kidwai
Keyword(s):  
Amino Acids ◽  
Catalytic Reduction ◽  
Alkaline Media

Homochirality as the Signature of Extra-Terrestrial Life

1997 ◽  
Vol 161 ◽  
pp. 505-510
Author(s):  
Alexandra J. MacDermott ◽  
Laurence D. Barron ◽  
Andrè Brack ◽  
Thomas Buhse ◽  
John R. Cronin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Optical Rotation ◽  
Physical Origin ◽  
Natural Choice ◽  
Rosetta Mission ◽  
Terrestrial Life ◽  
Subsurface Layers ◽  
Solar System Bodies ◽  
Origin Of Homochirality

AbstractThe most characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. We therefore suggest that a search for extra-terrestrial life can be approached as a Search for Extra- Terrestrial Homochirality (SETH). The natural choice for a SETH instrument is optical rotation, and we describe a novel miniaturized space polarimeter, called the SETH Cigar, which could be used to detect optical rotation as the homochiral signature of life on other planets. Moving parts are avoided by replacing the normal rotating polarizer by multiple fixed polarizers at different angles as in the eye of the bee. We believe that homochirality may be found in the subsurface layers on Mars as a relic of extinct life, and on other solar system bodies as a sign of advanced pre-biotic chemistry. We discuss the chiral GC-MS planned for the Roland lander of the Rosetta mission to a comet and conclude with theories of the physical origin of homochirality.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

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