Vegetation affects pool size and composition of amino acids in Tibetan alpine meadow soils

Geoderma ◽  
2018 ◽  
Vol 310 ◽  
pp. 44-52 ◽  
Author(s):  
Yanli Feng ◽  
Jing Wang ◽  
Kun Yuan ◽  
Wenzhen Zong ◽  
Ding Guo
Keyword(s):  
Amino Acids ◽  
Alpine Meadow ◽  
Pool Size

scholarly journals Metabolism of urea in late pregnancy and the possible contribution of amino acid carbon to glucose synthesis in sheep

1970 ◽  
Vol 24 (4) ◽  
pp. 905-915 ◽  
Author(s):  
J. V. Nolan ◽  
R. A. Leng
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Late Pregnancy ◽  
Pool Size ◽  
Entry Rate ◽  
Plasma Urea ◽  
Upper Limit ◽  
Pregnant Sheep ◽  
Potential Availability ◽  
Glucose Synthesis

1. Metabolism of urea in non-pregnant and pregnant sheep (1–25 d from term) has been examined. Injections of [14C]urea were used to estimate urea entry rate, urea pool size and urea space in sheep given 1000 g of a diet of equal parts of crushed oats and chaffed lucerne hay (daya) and in the same sheep 4 d after the ration had been reduced to 250 g (dayb).2. On both experimental days (aandb), mean pool size was greater (14% on day α, 29% on dayb) and urea space was greater (54% on day α, 24% on dayb) in pregnant animals than in non-pregnant animals; mean plasma urea concentrations were lower (35%) in the pregnant animals on day a but were not significantly different on dayb.3. The entry rate of urea was similar in all the animals on daya, but was significantly higher (34%) in pregnant than in non-pregnant animals on dayb. There was a significant decrease in urea entry rate in both pregnant (33%) and non-pregnant (86%) animals on dayb.4. The rate of excretion of urea was lower (26% on daya, 35% on dayb) in pregnant animals, indicating a higher (31% on day α, 40% on dayb) rate of degradation of urea in the digestive tract of pregnant as compared with non-pregnant sheep.5. Measurements of urea entry rate have been used to calculate the upper limit of amino acid deamination in pregnant and non-pregnant sheep, and this has been used as an indication of the potential availability of amino acid carbon for glucose synthesis. It is suggested that, at a maximum, amino acids may have contributed the carbon required for 63 g/d and 52 g/d of glucose on daysaandbrespectively.

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

2015 ◽  
Vol 5 (18) ◽  
pp. 3995-4005 ◽  
Author(s):  
Shuang Ma ◽  
Xiaoxue Zhu ◽  
Jing Zhang ◽  
Lirong Zhang ◽  
Rongxiao Che ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plant Uptake ◽  
Alpine Meadow

scholarly journals Metabolic heritage mapping: heterogenous pools of cytoplasmic nucleotide sugars are selectively utilized by various glycosyltransferases

2021 ◽  
Author(s):  
Paulina Sosicka ◽  
Bobby G Ng ◽  
Lauren E Pepi ◽  
Asif Shajahan ◽  
Maurice Wong ◽  
...  
Keyword(s):  
Amino Acids ◽  
De Novo ◽  
Pool Size ◽  
Protein Glycosylation ◽  
De Novo Synthesis ◽  
General Applicability ◽  
Individual Contributions ◽  
Nucleotide Sugars

Biosynthesis of macromolecules requires precursors such as sugars or amino acids, originating from exogenous/dietary sources, reutilization/salvage of degraded molecules or de novo synthesis. Since these sources are assumed to contribute to one homogenous pool, their individual contributions are often overlooked. Protein glycosylation uses monosaccharides from all the above sources to produce nucleotide sugars required to assemble hundreds of distinct glycans. Here we demonstrate that cells identify the origin/heritage of the monosaccharide, fucose, for glycosylation. We measured the contribution of GDP-fucose from each of these sources for glycan synthesis and found that different fucosyltransferases, individual glycoproteins, and linkage-specific fucose residues identify and select different GDP-fucose pools dependent on their heritage. This supports the hypothesis that GDP-fucose exists in multiple, distinct pools, not as a single homogenous pool. The selection is tightly regulated since the overall pool size remains constant. We present novel perspectives on monosaccharide metabolism, which may have general applicability.

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).

Prevalence of the pit and antipit in the genus Glycine

1987 ◽  
Vol 45 ◽  
pp. 986-987
Author(s):  
R. W. Yaklich ◽  
E. L. Vigil ◽  
W. P. Wergin
Keyword(s):  
Amino Acids ◽  
Endoplasmic Reticulum ◽  
Glycine Max ◽  
Seed Coat ◽  
Cell Types ◽  
Abaxial Surface ◽  
Legume Seed ◽  
Initial Report ◽  
Cone Cells ◽  
Glycine Max L

The legume seed coat is the site of sucrose unloading and the metabolism of imported ureides and synthesis of amino acids for the developing embryo. The cell types directly responsible for these functions in the seed coat are not known. We recently described a convex layer of tissue on the inside surface of the soybean (Glycine max L. Merr.) seed coat that was termed “antipit” because it was in direct opposition to the concave pit on the abaxial surface of the cotyledon. Cone cells of the antipit contained numerous hypertrophied Golgi apparatus and laminated rough endoplasmic reticulum common to actively secreting cells. The initial report by Dzikowski (1936) described the morphology of the pit and antipit in G. max and found these structures in only 68 of the 169 seed accessions examined.

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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