Studies on soil polysaccharides. II. The composition and properties in soils under pasture and under a fallow-wheat rotation

Soil Research ◽  
1968 ◽  
Vol 6 (2) ◽  
pp. 225 ◽  
Author(s):  
GD Swincer ◽  
JM Oades ◽  
DJ Greenland
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Extraction Procedure ◽  
Gel Filtration ◽  
Wheat Crop ◽  
Low Molecular Weight ◽  
Neutral Sugar ◽  
Sugar Composition ◽  
High Molecular Weight Material ◽  
Neutral Sugars

After the removal of light fraction from soils under old pasture and under continuous fallow-wheat rotation, carbohydrates were extracted using IN HC1 followed by 0.5N NaOH and finally an acidic acetylation procedure, or by a single extraction with 0.2N NaOH only. The sequential extraction procedure removed 70-80 % of the carbohydrate from the soil under both agronomic systems. 0.2N NaOH removed a larger proportion of the carbohydrates from soil under fallow-wheat rotation (43-52%) than from soil under old pasture (35-38%). The composition of the carbohydrates in a given extract from the soil under pasture or fallow-wheat was similar. This similarity extended even to the neutral sugar composition of fractions obtained by gel filtration of the purified extracts. Generally, low molecular weight materials were rich in amino acids and compounds such as glucose, ribose, and glycerol. Polymers of molecular weight 4000-100,000 contained relatively high proportions of uronic acids and amino acids. Least amino acids were present in materials of molecular weight greater than 100,000 which contained appreciable quantities of deoxyhexoses (up to 20% of the total neutral sugars) indicative of their microbial origin. Against this background of similarity, certain differences between the carbohydrates from soils under pasture and fallow-wheat rotation were apparent. 1N HCl extracts contained more high molecular weight material from the old pasture soils than from the cultivated soil. The composition of these extracts indicated that they comprised the easily extractable recently synthesized microbial polysaccharides. The proportion of such polymers was lower in the cropped soil. A higher proportion of materials of small size was present in soils under a wheat crop. Maximum amounts of these compounds were present during periods of maximum plant and microbial activity. Extracts from soils under fallow-wheat rotation contained a higher proportion of uronic and amino acids and less ribose, arabinose, and deoxysugars than the extracts from soils under pasture. Based on relative deoxysugar contents it was calculated that the pasture soil contains about four times as much microbial polysaccharide as the soil under fallow-wheat.

In Vivo Studies on the Inhibition of Coagulation by Fractionated Heparin and by a Heparin Analogue I. Effects of Heparin Fractions

1981 ◽  
Vol 46 (03) ◽  
pp. 612-616 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Day Treatment ◽  
Gel Filtration ◽  
Weight Fraction ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Platelet Factor ◽  
Heparin Fractions

SummaryHigh and low molecular weight heparin fractions obtained by gel filtration chromatography of sodium mucosal heparin were injected subcutaneously into six healthy volunteers and compared with the unfractionated substance in a cross-over trial. Equal doses of 5,000 U were administered twice daily over a period of three days and heparin activity was repeatedly controlled before and 2, 4, 8 hrs after injection by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of subcutaneously administered fractionated heparin on platelet function was examined on three of the volunteers. The results show that s.c. injections of the low molecular weight fraction induced markedly higher anti-Xa activity than injections of the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the high molecular weight fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA production, while the low molecular weight fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of platelet Factor 4 in plasma. During the three-day treatment periods, no side-effects and no significant changes in the response to heparin injections were detected.

Characterization of an isozyme of S-adenosylmethionine synthetase from rat liver

1984 ◽  
Vol 62 (5) ◽  
pp. 276-279 ◽  
Author(s):  
C. H. Lin ◽  
W. Chung ◽  
K. P. Strickland ◽  
A. J. Hudson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Enzymatic Synthesis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Aromatic Amino Acids ◽  
Adenosylmethionine Synthetase ◽  
Cellulose Column

An isozyme of S-adenosylmethionine synthetase has been purified to homogeneity by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and gel filtration on a Sephadex G-200 column. The purified enzyme is very unstable and has a molecular weight of 120 000 consisting of two identical subunits. Amino acid analysis on the purified enzyme showed glycine, glutamate, and aspartate to be the most abundant and the aromatic amino acids to be the least abundant. It possesses tripolyphosphatase activity which can be stimulated five to six times by S-adenosylmethionine (20–40 μM). The findings support the conclusion that an enzyme-bound tripolyphosphate is an obligatory intermediate in the enzymatic synthesis of S-adenosylmethionine from ATP and methionine.

Difunctional enols of N-protected amino acids as low molecular weight and novel inhibitors of HIV-1 protease.

1993 ◽  
Vol 3 (6) ◽  
pp. 1169-1174 ◽  
Author(s):  
Marc Vaillancourt ◽  
Benoit Vanasse ◽  
Eric Cohen ◽  
Gilles Sauv
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Low Molecular Weight ◽  
Hiv 1

HEMODIALYSIS OF THE RAT

1966 ◽  
Vol 44 (5) ◽  
pp. 849-859 ◽  
Author(s):  
Sumner M. Robinson ◽  
David A. Hurwitz ◽  
Robert Louis-Ferdinand ◽  
William F. Blatt
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Low Molecular Weight

A technique is described for hemodialysis of either anesthetized or non-restrained rats. In the apparatus the dialysis plates of an autoanalyzer system are used with only minor modification. The efficiency of this method has been evaluated with regard to the clearance of saccharides, both in vitro and in vivo, as well as the extraction of nitrogenous low molecular weight moieties from circulating blood. Approximately 50% of the dialyzable material was obtained in a 1-hour dialysis. Further fractionation of the dialyzate was accomplished by gel filtration (Sephadex G-25).

scholarly journals The Nature of the Muscle-Relaxing Factor

1963 ◽  
Vol 46 (5) ◽  
pp. 893-904 ◽  
Author(s):  
Franklin Fuchs ◽  
F. Norman Briggs
Keyword(s):  
Molecular Weight ◽  
High Speed ◽  
Gel Filtration ◽  
Active Agent ◽  
Calcium Deficiency ◽  
Chelating Resin ◽  
Prolonged Heating ◽  
Relaxing Factor ◽  
Chelex 100 ◽  
High Molecular Weight Material

High speed centrifugal fractionation of homogenates of rabbit skeletal muscle has led to the discovery of a soluble muscle-relaxing factor in the homogenate. Assay of the relaxing activity with deoxycholate-treated myofibrils and reconstituted actomyosin systems has established that the activity is not produced by the presence of contaminants. Relaxing activity could be removed or destroyed by charcoal, dialysis, prolonged heating, and treatment with the chelating resin, chelex-100, making it improbable that the effect is due simply to calcium deficiency. Many of the characteristics of this muscle-relaxing factor suggest that it is very similar to or the same as the factor formed by the incubation of muscle granule fractions and ATP. Evidence is presented that some soluble protein component is involved in the stabilization of the factor. The relaxing activity could be separated from the high molecular weight material in the supernatant by the technique of gel filtration. On the basis of the gel used, the molecular weight of the active agent should be less than 4000.

scholarly journals Role of serum IgA. Hepatobiliary transport of circulating antigen.

1981 ◽  
Vol 153 (4) ◽  
pp. 968-976 ◽  
Author(s):  
M W Russell ◽  
T A Brown ◽  
J Mestecky
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Serum Iga ◽  
Circulating Antigen ◽  
Circulating Antigens ◽  
Iga Antibody ◽  
Immune Spleen Cell

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.

scholarly journals High Molecular Weight Factor VIII Coagulant Activity in Cryoprecipitate and Polyethylene Glycol Precipitates

1977 ◽  
Author(s):  
K. A. Rickard ◽  
T. Exner ◽  
H. Kronenberg
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Factor Viii ◽  
High Molecular Weight ◽  
Gel Filtration ◽  
Lower Molecular Weight ◽  
Human Antibody ◽  
High Molecular Weight Material ◽  
Coagulant Activity ◽  
Molecular Weight Form

Gel filtration of human plasma cryoprecipitate on Sepharose 2B indicated the molecular weight of factor VIII coagulant activity (VIIIc) to be significantly greater than that found in antihaemophilic concentrate. Polyethylene glycol at 3% concentration precipitated approximately half of the VIIIc from cryoprecipitate. This activity eluted as high molecular weight material on gel filtration. The addition of more polyethylene glycol to a concentration of 8% precipitated most of the remaining VIIIc from cryoprecipitate. This activity appeared to be of significantly lower molecular weight, approximately corresponding in elution volume to that observed for antihaemophilic concentrate. The possibility that an antibody to VIIIc generated in a patient treated with cryoprecipitate might be directed against the higher molecular weight form of factor VIII was investigated. However, no significant differences between the higher and lower molecular weight forms of factor VIII either in stability or in reactivity with human antibody to factor VIII were found.

In Vivo Studies On The Inhibition Of Coagulation By Fractionated Heparin

1981 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Gel Filtration ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Chromogenic Substrate ◽  
Serotonin Content ◽  
Heparin Activity ◽  
Heparin Fractions

Recent investigations suggest that low molecular weight heparin may have advantages over conventional heparin with regard to the prevention of venous thrombosis and haemorrhagic side effects.High (HMW) and low (LMW) molecular weight heparin fractions with mean MWs of 16,000 and 8,800 respectively, obtained by gel filtration chromatography of sodium mucosal heparin (B. Braun Melsungen), were injected subcutaneously into six volunteers and compared with the unfractionated substance in a cross-over trial. Doses of 5,000 U were administered twice daily over a period of three days and heparin activity was controlled before injection and 2,4,8 hours afterwards by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of fractionated heparin on platelet function was examined. The results show that the LMW fraction induced markedly higher anti-Xa activity than the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the HMW fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA-production, while the LMW fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of PF IV, whereas the serotonin content of platelets determined at the same time increased.It is concluded that s.c. injections of LMW heparin induce relatively high levels of anti-Xa activity without leading to sensitive platelet activation or to major effects on overall clotting tests.

scholarly journals Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

2014 ◽  
Vol 11 (19) ◽  
pp. 5349-5363 ◽  
Author(s):  
L. Jørgensen ◽  
O. J. Lechtenfeld ◽  
R. Benner ◽  
M. Middelboe ◽  
C. A. Stedmon
Keyword(s):  
Amino Acids ◽  
Unknown Origin ◽  
Molecular Composition ◽  
Bacterial Degradation ◽  
The Arctic ◽  
Striking Similarity ◽  
Neutral Sugar ◽  
Natural Seawater ◽  
Glucose Content ◽  
Neutral Sugars

Abstract. Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay incubations with natural seawater (sampled from water masses originating from the surface waters of the Arctic Ocean and the North Atlantic Ocean) and artificial seawater indicate that the molecular compositions following bacterial degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol %) and heterogeneous contributions from other neutral sugars (3–14 mol %). DOM remaining after bacterial degradation was characterized by a high galactose content (33 mol %), followed by glucose (22 mol %) and the remaining neutral sugars (7–11 mol %). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days, the D/L ratios of aspartic acid, glutamic acid, serine and alanine reached around 0.79, 0.32, 0.30 and 0.51 in all treatments, respectively. The striking similarity in neutral sugar and amino acid compositions between natural (representing marine semi-labile and refractory DOM) and artificial (representing bacterially produced DOM) seawater samples, suggests that microbes transform bioavailable neutral sugars and amino acids into a common, more persistent form.

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