THE ISOLATION OF SOIL HUMIC AND FULVIC ACID COMPONENTS RICH IN "UNKNOWN NITROGEN"

1983 ◽  
Vol 63 (3) ◽  
pp. 425-433 ◽  
Author(s):  
M. SCHNITZER ◽  
P. R. MARSHALL ◽  
D. A. HINDLE
Keyword(s):  
Molecular Weight ◽  
Fulvic Acid ◽  
Gel Filtration ◽  
Ammonia Nitrogen ◽  
Water Soluble ◽  
Soil N ◽  
Total N ◽  
Soil N Cycle ◽  
The Many ◽  
Molecular Weight Fractions

Close to 50% of the total N in soils has so far not been identified. Previous studies indicate that this "unknown" N might be bio-available and may participate in the soil N cycle. The objective of this investigation was to develop a procedure which would allow us to isolate from soils, fractions which were rich in unknown N but which would contain only small amounts of known N compounds. We felt that the availability of such fractions would permit us to learn more about the characteristics of the unknown N components without too much interference from the many known N-containing constituents. The isolation procedure involved (a) the extraction and separation of humic (HA) and fulvic acid (FA) fractions from soils; (b) hydrolysis of each fraction with hot 6 mol∙L−1 HCl; (c) separation of neutralized hydrolyzates on Sephadex G-25 gel; and (d) further separation of the highest molecular weight fractions of the neutralized hydrolyzates on G-50 gel, and of the second highest molecular weight fractions on G-15 gel. For soil samples taken from the Ah horizon of the Bainsville soil (a Humic Gleysol) and the Bh horizon of the Armadale (a Podzol), proportions of soil-N in HAs and FAs, and in fractions derived from them were, in HAs + FAs, 29.3 and 56.9%; in water-soluble, hydrolyzed HA- and FA- fractions, 12.0 and 19.7%; and in nonhydrolyzable and water-insoluble (at pH 7) fractions, 9.0 and 16.3%, respectively. Substantial portions of the soil N were left unextracted in the humins. Several fractions were isolated by the procedure described herein; in some close to 98% of the total N consisted of unknown N. Key words: Amino acid nitrogen, ammonia nitrogen, acid hydrolysis, gel filtration

Existence of lipid vesicles containing platelet-activating factor in endothelial cell lysate

1992 ◽  
Vol 12 (1) ◽  
pp. 15-21
Author(s):  
S. Kojima ◽  
K. Nara ◽  
Y. Inada ◽  
S. Hirose ◽  
Y. Saito
Keyword(s):  
Molecular Weight ◽  
Endothelial Cell ◽  
Specific Activity ◽  
Gel Filtration ◽  
Platelet Activating Factor ◽  
Lipid Vesicles ◽  
Specific Factor ◽  
Cell Lysate ◽  
Aggregation Activity ◽  
Molecular Weight Fractions

Platelet aggregation activity due to platelet-activating factor (PAF) was detected at high molecular weight (HMW) and low molecular weight fractions after gel-filtration chromatography of cell lysate of endothelial cells. [3H]PAF added to the cell lysate was similarly distributed after chromatography. The radioactivity associated with HMW fraction was not reduced by digesting the lysate with trypsin, suggesting that PAF was not making complexes with proteins but was included in lipid vesicles in cell lysate. Further evidence showed that an unknown specific factor(s) was needed to form these PAF-containing lipid vesicles. Radioactivity was not found in HMW fraction when [3H]PAF was mixed with cell lysate of vascular smooth muscle cells. When monomeric PAF was added to endothelial cell lysate, the specific activity of aggregation decreased to the level exerted by endogenous PAF-containing lipid vesicles due to incorporation into lipid vesicles. PAF in the form of lipid vesicles was more stable in plasma than monomeric form.

scholarly journals α-Crystallin. The isolation and characterization of distinct macromolecular fractions

1971 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Abraham Spector ◽  
Lu-Ku Li ◽  
Robert C. Augusteyn ◽  
Arthur Schneider ◽  
Thomas Freund
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Chemical Difference ◽  
Molecular Weights ◽  
Isolation And Characterization ◽  
Different Populations ◽  
Molecular Weight Fractions

α-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6×105−9×105, 0.9×106−4×106and greater than 10×106. The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65–75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5×103and 22.5×103were observed for all α-crystallin fractions.

scholarly journals The soil N cycle: new insights and key challenges

SOIL ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 235-256 ◽  
Author(s):  
J. W. van Groenigen ◽  
D. Huygens ◽  
P. Boeckx ◽  
Th. W. Kuyper ◽  
I. M. Lubbers ◽  
...  
Keyword(s):  
N Cycling ◽  
Greenhouse Gas Mitigation ◽  
Future Research ◽  
N Fixation ◽  
Gaseous Emissions ◽  
Soil N ◽  
Personal View ◽  
Total N ◽  
N Cycle ◽  
Soil N Cycle

Abstract. The study of soil N cycling processes has been, is, and will be at the centre of attention in soil science research. The importance of N as a nutrient for all biota; the ever-increasing rates of its anthropogenic input in terrestrial (agro)ecosystems; its resultant losses to the environment; and the complexity of the biological, physical, and chemical factors that regulate N cycling processes all contribute to the necessity of further understanding, measuring, and altering the soil N cycle. Here, we review important insights with respect to the soil N cycle that have been made over the last decade, and present a personal view on the key challenges of future research. We identify three key challenges with respect to basic N cycling processes producing gaseous emissions: 1. quantifying the importance of nitrifier denitrification and its main controlling factors; 2. characterizing the greenhouse gas mitigation potential and microbiological basis for N2O consumption; 3. characterizing hotspots and hot moments of denitrification Furthermore, we identified a key challenge with respect to modelling: 1. disentangling gross N transformation rates using advanced 15N / 18O tracing models Finally, we propose four key challenges related to how ecological interactions control N cycling processes: 1. linking functional diversity of soil fauna to N cycling processes beyond mineralization; 2. determining the functional relationship between root traits and soil N cycling; 3. characterizing the control that different types of mycorrhizal symbioses exert on N cycling; 4. quantifying the contribution of non-symbiotic pathways to total N fixation fluxes in natural systems We postulate that addressing these challenges will constitute a comprehensive research agenda with respect to the N cycle for the next decade. Such an agenda would help us to meet future challenges on food and energy security, biodiversity conservation, water and air quality, and climate stability.

IDENTIFICATION AND PURIFICATION OF A NEW PROTEIN FROM WATER-SOLUBLE EXTRACTS OF HUMAN ADRENAL GLAND

1979 ◽  
Vol 82 (3) ◽  
pp. 383-NP ◽  
Author(s):  
M. A. AL-AWQATI ◽  
Y. B. GORDON ◽  
T. CHARD
Keyword(s):  
Molecular Weight ◽  
Adrenal Gland ◽  
Gel Filtration ◽  
Water Soluble ◽  
Double Immunodiffusion ◽  
Molecular Weights ◽  
Physicochemical Methods ◽  
Two Peaks ◽  
Sepharose 4B ◽  
New Protein

An homogenate of human foetal adrenal gland was subjected to negative immunoabsorption by column chromatography using anti-whole human serum coupled to Sepharose 4B. Two peaks were eluted and used to immunize rabbits. The antisera produced were absorbed and tested for specificity by double immunodiffusion. Two antigens, which appeared to be specific to the adrenal gland, were identified having molecular weights of 25 000 and 65 000 as determined by gel filtration. The lower molecular weight antigen was isolated by physicochemical methods and found to be a protein. The amino acid composition is reported.

Fractionation of the Color of Pure Maple and Other Sirups by Gel Filtration

1965 ◽  
Vol 48 (3) ◽  
pp. 493-497
Author(s):  
E E Stinson ◽  
C O Willits
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Cane Sugar ◽  
The Other ◽  
Low Molecular Weight ◽  
Brown Sugar ◽  
Maple Sugar ◽  
Molecular Weight Fractions ◽  
Color Fraction

Abstract The colorants of pure maple, cane and maple, refined cane sugar, and light brown sugar sirups were separated into two fractions, one of high- and the other of lowmolecular weights, by means of gel filtration. The ratio of the amounts of high- to the low-molecular weight fractions of pure maple was the lowest of the four sirups and serves as a means of differentiation from these sirups. The color fraction ratio was highest for blended cane-maple sugar sirup. Many maple sirups are also distinguished by a pink band formed on the gel filtration column.

A Potent Insect Chitinase Inhibitor of Fungal Origin

2003 ◽  
Vol 58 (11-12) ◽  
pp. 891-894 ◽  
Author(s):  
Teruhiko Nitoda ◽  
Hirokazu Usuki ◽  
Hiroshi Kanzaki
Keyword(s):  
Molecular Weight ◽  
Anion Exchange ◽  
Culture Filtrate ◽  
Inhibitory Activity ◽  
Spodoptera Litura ◽  
Gel Filtration ◽  
Fungal Strain ◽  
Water Soluble ◽  
Gel Filtration Chromatography ◽  
Soluble Polysaccharide

Abstract A water-soluble polysaccharide was isolated from the culture filtrate of a fungal strain, Sphaeropsis sp. TNPT116-Cz, as a novel insect chitinase inhibitor. It was purified to chromatographic homogeneity by ethanol precipitation, anion-exchange and gel filtration chromatography. Its molecular weight was estimated to be 16 kDa by gel filtration HPLC. Monosaccharide analysis showed that it contained glucose, galactose, N-acetylglucosamine and a deoxysugar. This polysaccharide showed potent and specific inhibitory activity against Spodoptera litura chitinase with an IC50 value of 28 nᴍ.

Water-soluble lysine-containing polypeptides. IV. The synthesis, characterization,and circular dichroism spectra of sequential polypeptides formed from dipeptides of lysine and amino acids of increasing side chain size

1977 ◽  
Vol 55 (24) ◽  
pp. 4257-4266 ◽  
Author(s):  
Lewis A. Slotin ◽  
Denis R. Lauren ◽  
Ross E. Williams
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Gel Filtration ◽  
Circular Dichroism Spectroscopy ◽  
Water Soluble ◽  
Side Chain ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm

Several polypeptides have been synthesized which contain the alternating sequence lysyl-X, where X = gly, L-ala, D-ala, L-val, L-leu, and L-phe. The polypeptides have been characterized by gel filtration (molecular weight) and by circular dichroism spectroscopy (secondary structure).

scholarly journals Cloud Condensation Nuclei properties of model and atmospheric HULIS

2006 ◽  
Vol 6 (9) ◽  
pp. 2465-2482 ◽  
Author(s):  
E. Dinar ◽  
I. Taraniuk ◽  
E. R. Graber ◽  
S. Katsman ◽  
T. Moise ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Fulvic Acid ◽  
Atmospheric Aerosols ◽  
Cloud Condensation Nuclei ◽  
Average Molecular Weight ◽  
Water Soluble ◽  
Cloud Droplets ◽  
Secondary Sources ◽  
Multifunctional Compounds ◽  
Physico Chemical

Abstract. Humic like substances (HULIS) have been identified as a major fraction of the organic component of atmospheric aerosols. These large multifunctional compounds of both primary and secondary sources are surface active and water soluble. Hence, it is expected that they could affect activation of organic aerosols into cloud droplets. We have compared the activation of aerosols containing atmospheric HULIS extracted from fresh, aged and pollution particles to activation of size fractionated fulvic acid from an aquatic source (Suwannee River Fulvic Acid), and correlated it to the estimated molecular weight and measured surface tension. A correlation was found between CCN-activation diameter of SRFA fractions and number average molecular weight of the fraction. The lower molecular weight fractions activated at lower critical diameters, which is explained by the greater number of solute species in the droplet with decreasing molecular weight. The three aerosol-extracted HULIS samples activated at lower diameters than any of the size-fractionated or bulk SRFA. The Köhler model was found to account for activation diameters, provided that accurate physico-chemical parameters are known.

scholarly journals A comparative study on the preparation of immunoglobulin-galactosidase conjugates.

1981 ◽  
Vol 29 (11) ◽  
pp. 1273-1280 ◽  
Author(s):  
A M Deelder ◽  
R de Water
Keyword(s):  
Molecular Weight ◽  
Coupling Agent ◽  
Gel Filtration ◽  
The Other ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chromogenic Substrate ◽  
Fluorogenic Substrate ◽  
Detection Level ◽  
Lower Detection ◽  
Molecular Weight Fractions

For the application of beta-D-galactosidase-immunoglobulin conjugates in the enzyme-linked immunosorbent assay (ELISA), four techniques for the preparation of such conjugates were compared. Sheep immunoglobulin (Ig) (against soluble egg antigens of the trematode Schistosoma mansoni) was coupled to beta-D-galactosidase by means of 1) glutaraldehyde treatment, 2) the heterobifunctional reagent N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP), and 3,4) two different procedures using the coupling agent m-maleimidobenzoyl-N-hydroxysuccinimide ester(MBS). The prepared conjugates were then fractionated by gel filtration on Sepharose 6B and the resultant molecular weight fractions were tested in an ELISA for the detection of S. mansoni antigen. Optimal results were obtained with a conjugate that was synthesized according to one of the two techniques using MBS. With this conjugate, 10(-9) g antigen/ml could still be detected in an ELISA with a chromogenic substrate, which was at least ten times as sensitive as with the other conjugates. Application of a fluorogenic substrate resulted in a lower detection level of 10(-10) g antigen/ml.

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