Orthophosphate and its Flux in Lake Waters

1981 ◽  
Vol 38 (10) ◽  
pp. 1215-1219 ◽  
Author(s):  
E. White ◽  
G. Payne ◽  
S. Pickmere ◽  
F. R. Pick
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Organic Phosphorus ◽  
Particulate Material ◽  
Major Influence ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Near Surface ◽  
Molybdenum Blue ◽  
Dominant Component

Molybdate reactive high molecular weight (MW > 5000) phosphorus (RHMW-P) in solution was separated from low molecular weight material (PO4-P) by Sephadex gel (G25–150). PO4-P is as close to orthophosphate as has been possible to achieve with molybdenum blue technology. Chromatograms of near-surface waters of 32 lakes showed that RHMW-P was rarely the dominant component of dissolved reactive phosphorus (DRP), and so cannot be the major influence causing discrepant estimates of orthophosphate concentrations derived from molybdenum blue and radiotracer technology. The low molecular weight material (PO4-P) may still contain chemically reactive organic phosphorus which could lead to overestimation of orthophosphate. Recent literature points to discrepancies in radiotracer estimates too, so further effort is required to provide reliable assessment of orthophosphate in lake water. Estimates of orthophosphate flux from solution to particulate material based on 32PO4-derived turnover times are likely to be in error irrespective of the source of orthophosphate estimate.Key words: molybdenum blue method, radiotracer, orthophosphate flux, reactive high molecular weight phosphorus, gel chromatography, radiobioassay

scholarly journals Structure Analysis and Anti-Tumor and Anti-Angiogenic Activities of Sulfated Galactofucan Extracted from Sargassum thunbergii

Marine Drugs ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 52 ◽  
Author(s):  
Weihua Jin ◽  
Wanli Wu ◽  
Hong Tang ◽  
Bin Wei ◽  
Hong Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Structure Analysis ◽  
Nmr Spectra ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Sargassum Thunbergii ◽  
Sulfation Pattern ◽  
Fucose Content

Sulfated galactofucan (ST-2) was obtained from Sargassum thunbergii. It was then desulfated to obtain ST-2-DS, and autohydrolyzed and precipitated by ethanol to obtain the supernatant (ST-2-S) and precipitate (ST-2-C). ST-2-C was further fractionated by gel chromatography into two fractions, ST-2-H (high molecular weight) and ST-2-L (low molecular weight). Mass spectrometry (MS) of ST-2-DS was performed to elucidate the backbone of ST-2. It was shown that ST-2-DS contained a backbone of alternating galactopyranose residues (Gal)n (n ≤ 3) and fucopyranose residues (Fuc)n. In addition, ST-2-S was also determined by MS to elucidate the branches of ST-2. It was suggested that sulfated fuco-oligomers might be the branches of ST-2. Compared to the NMR spectra of ST-2-H, the spectra of ST-2-L was more recognizable. It was shown that ST-2-L contain a backbone of (Gal)n and (Fuc)n, sulfated mainly at C4 of Fuc, and interspersed with galactose (the linkages were likely to be 1→2 and 1→6). Therefore, ST-2 might contain a backbone of (Gal)n (n ≤ 3) and (Fuc)n. The sulfation pattern was mainly at C4 of fucopyranose and partially at C4 of galactopyranose, and the branches were mainly sulfated fuco-oligomers. Finally, the anti-tumor and anti-angiogenic activities of ST-2 and its derivates were determined. It was shown that the low molecular-weight sulfated galactofucan, with higher fucose content, had better anti-angiogenic and anti-tumor activities.

"Colloidal" Phosphorus Errors in Gel Chromatography

1983 ◽  
Vol 40 (10) ◽  
pp. 1614-1621 ◽  
Author(s):  
B. Kent Burnison
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
High Molecular Weight ◽  
Gel Chromatography ◽  
Chemical Analyses ◽  
Molybdophosphoric Acid ◽  
Molybdenum Blue ◽  
Soluble Reactive Phosphate ◽  
Colloidal Phosphorus ◽  
Hydrolysis Of

Gel chromatography has been used for the separation of 32PO4 and a high molecular weight "colloidal" 32P-labeled fraction from 32PO4-labeled lakewater. When the labeled filtrate is treated with reagents required for the molybdenum blue method for orthophosphate analysis, only a small fraction of the "colloidal" peak is hydrolyzed to orthophosphate. As the reduced molybdophosphoric acid is strongly adsorbed to the dextran gel, quantitative elution of 32PO4 can be achieved with 0.05 mol∙L−1 NaOH and 0.3% NaCl. In hardwater lakes, care must be taken to eliminate the possibility of orthophosphate precipitation at higher pH. In these lakes, it is unlikely that the discrepancy between 32PO4 bioassays and chemical analyses can be solely attributed to acid hydrolysis of "colloidal" phosphorus. Microparticulate apatite also has the potential to release soluble reactive phosphate when the acidic molybdenum blue method is used.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

The Relation Between VIIIR:AG and VIII:C Studied with Two Antisera

1979 ◽  
Author(s):  
H. P. Muller ◽  
N. H. van Tilburg ◽  
R. M. Bertina ◽  
J. J. Veltkamp
Keyword(s):  
Molecular Weight ◽  
High Salt ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Specific Antibodies ◽  
Specific Effects ◽  
Normal Plasma ◽  
Coagulant Activity ◽  
Sterical Hindrance ◽  
Inhibitory Antibodies

FVIII was separated into low molecular weight FVIII (LMW FVIII) and high molecular weight FVIII (HMW FVIII) by gel chromatography in the presence of high salt concentration or by high salt elution of LMW FVIII from FVIII bound to anti HMW FVII-Sepharose. Specific antibodies were raised in rabbits against HMW FVIII and LMW FVIII. After removal of the contaminating anti HMW activities the rabbit anti LMW FVIII was still able to neutralize the FVIII coagulant activity of normal plasma and of IMW FVIII with canparable efficiency and it had no effect on the VIIIR:WF of FVIII in normal plasma or in HMW FVIII. Anti LMW FVIII does not bind to HMW FVIII and does not precipitate FVIII as tested by counter immunoelectrophoresis. Rabbit anti HMW FVIII precipitates FVIII in normal plasma, inhibits VIIIR:WF activity, while it has no effect on the FVIII coagulant activity of LMW FVIII. The coagulant activity of FVIII in normal plasma is slightly inhibited by anti HMW FVIII presumably by non-specific effects (sterical hindrance). It is concluded that inhibitory antibodies against VIII:C raised in rabbits recognize antigenic structures only present on LMW FVIII. Antibodies against HMW FVIII raised in rabbits appears to recognize structures only present on HMW FVIII.

scholarly journals Antiparasitic antibodies occur with similar frequency in patients with clinically established multiple sclerosis with or without oligoclonal bands in the cerebrospinal fluid

2013 ◽  
Vol 71 (8) ◽  
pp. 512-515 ◽  
Author(s):  
Fabiana Cruz Gomes da Fonseca-Papavero ◽  
Dagoberto Callegaro ◽  
Paulo Diniz da Gama ◽  
Jose Antonio Livramento ◽  
Adelaide Jose Vaz ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Hygiene Hypothesis ◽  
Oligoclonal Bands ◽  
Parasitic Infections ◽  
Low Molecular Weight ◽  
Serum Samples ◽  
Similar Frequency ◽  
Electrophoresis Of Proteins

The "hygiene hypothesis" postulates an inverse relationship between the prevalence of parasitic infections and the frequency of multiple sclerosis (MS). Objective: It was to study whether antibodies against parasites could be demonstrated more frequently in blood serum from MS patients with oligoclonal bands (OCB) than from MS patients without OCB. Methods: We studied serum samples from 164 patients who had previously been analyzed to investigate OCB. Parasitic antibodies were studied through unidimensional electrophoresis of proteins on polyacrylamide gel against Taenia antigens, searching for antiparasitic specific low molecular weight antibodies and also for antiparasitic nonspecific high molecular weight antibodies. Results: Two of the 103 patients with no evidence of OCB had antibodies of low molecular weight and 59 of them had antibodies of high molecular weight. Of the 61 patients with evidence of OCB, one showed antibodies of low molecular weight and 16 showed antibodies of high molecular weight. Conclusion: Antiparasitic antibodies are detected with similar frequency in MS patients with OCB and in MS patients without OCB.

Hepatic Metallothionein in Rainbow Trout (Salmo gairdneri) as an Indicator of Metal Pollution in the Campbell River System

1982 ◽  
Vol 39 (12) ◽  
pp. 1596-1601 ◽  
Author(s):  
M. Roch ◽  
J. A. McCarter ◽  
A. T. Matheson ◽  
M. J. R. Clark ◽  
R. W. Olafson
Keyword(s):  
Molecular Weight ◽  
Rainbow Trout ◽  
Metal Pollution ◽  
Quantitative Measure ◽  
Salmo Gairdneri ◽  
Differential Pulse Polarography ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Hepatic Metallothionein ◽  
Molecular Weight Fractions

Hepatic metallothionein was measured in livers of freshly killed rainbow trout (Salmo gairdneri) using differential pulse polarography. The fish were caught in metal-contaminated lakes of the Campbell River watershed and in a nearby control lake. The livers were analyzed for zinc, copper, and cadmium using atomic absorption spectrophotometry. High and low molecular weight protein fractions were separated by gel chromatography from liver cytosols and analyzed for metals. A downward trend from the most contaminated lake to the least was found in levels of zinc in the water, of cadmium and copper in high molecular weight fractions, and of copper in low molecular weight fractions and metallothionein. The concentration of metallothionein is a useful quantitative measure of the degree of exposure of fish to heavy metals.Key words: metallothionein, rainbow trout, Salmo gairdneri; heavy metal pollution, sublethal exposures, mine wastes

Simultaneous Isolation of Wheat High Molecular Weight and Low Molecular Weight Glutenin Subunits

1998 ◽  
Vol 28 (1) ◽  
pp. 25-32 ◽  
Author(s):  
I.M. Verbruggen ◽  
W.S. Veraverbeke ◽  
A. Vandamme ◽  
J.A. Delcour
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Glutenin Subunits

scholarly journals The interrelations between high- and low-molecular-weight forms of normal and mutant (Krabbe-disease) galactocerebrosidase

1980 ◽  
Vol 189 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yoav Ben-Yoseph ◽  
Melinda Hungerford ◽  
Henry L. Nadler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Krabbe Disease ◽  
Low Molecular Weight ◽  
Molecular Weight Form

Galactocerebrosidase (β-d-galactosyl-N-acylsphingosine galactohydrolase; EC 3.2.1.46) activity of brain and liver preparations from normal individuals and patients with Krabbe disease (globoid-cell leukodystrophy) have been separated by gel filtration into four different molecular-weight forms. The apparent mol.wts. were 760000±34000 and 121000±10000 for the high- and low-molecular-weight forms (peaks I and IV respectively) and 499000±22000 (mean±s.d.) and 256000±12000 for the intermediate forms (peaks II and III respectively). On examination by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the high- and low-molecular-weight forms revealed a single protein band with a similar mobility corresponding to a mol.wt. of about 125000. Antigenic identity was demonstrated between the various molecular-weight forms of the normal and the mutant galactocerebrosidases by using antisera against either the high- or the low-molecular-weight enzymes. The high-molecular-weight form of galactocerebrosidase was found to possess higher specific activity toward natural substrates when compared with the low-molecular-weight form. It is suggested that the high-molecular-weight enzyme is the active form in vivo and an aggregation process that proceeds from a monomer (mol.wt. approx. 125000) to a dimer (mol.wt. approx. 250000) and from the dimer to either a tetramer (mol.wt. approx. 500000) or a hexamer (mol.wt. approx. 750000) takes place in normal as well as in Krabbe-disease tissues.

Sign in / Sign up

Export Citation Format

Share Document