STUDIES ON THE ISOLATION AND NATURE OF THE 'TERREGENS FACTOR'

1954 ◽  
Vol 32 (1) ◽  
pp. 400-406 ◽  
Author(s):  
M. O. Burton ◽  
F. J. Sowden ◽  
A. G. Lochhead
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Ferric Iron ◽  
Test Organism ◽  
The Other ◽  
Inorganic Salts ◽  
Low Molecular Weight ◽  
Straight Chain ◽  
Heat Stable ◽  
Growth Promoting

A procedure is described for the production and concentration of the 'terregens factor' (TF), a bacterial growth promoting substance synthesized by Arthrobacter pascens and essential for the growth of Arthrobacter terregens. From culture filtrates of A. pascens cultivated in a medium of inorganic salts and sucrose, concentrates of TF may be obtained that are active at 0.001 μgm. Per ml., heat stable and contain about 12.7% nitrogen. Acid hydrolysis yielded a number of amino acids, including glutamic acid, glycine, α–alanine, valine, leucine, proline, lysine, and arginine, as well as some unidentified compounds; however, TF does not appear to be a low molecular weight straight chain peptide.Although TF contains no iron, it combines readily with ferrous or ferric iron to form reddish-brown complexes with this metal. Activity for A. terregens is shown by certain iron containing complexes as hemin, coprogen, and ferrichrome. On the other hand none is shown by cytochrome or pulcherrimin; however, aspergillic acid, structurally related to the latter, possesses some growth promoting activity for the test organism.

STUDIES ON THE ISOLATION AND NATURE OF THE 'TERREGENS FACTOR'

1954 ◽  
Vol 32 (4) ◽  
pp. 400-406 ◽  
Author(s):  
M. O. Burton ◽  
F. J. Sowden ◽  
A. G. Lochhead
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Ferric Iron ◽  
Test Organism ◽  
The Other ◽  
Inorganic Salts ◽  
Low Molecular Weight ◽  
Straight Chain ◽  
Heat Stable ◽  
Growth Promoting

A procedure is described for the production and concentration of the 'terregens factor' (TF), a bacterial growth promoting substance synthesized by Arthrobacter pascens and essential for the growth of Arthrobacter terregens. From culture filtrates of A. pascens cultivated in a medium of inorganic salts and sucrose, concentrates of TF may be obtained that are active at 0.001 μgm. Per ml., heat stable and contain about 12.7% nitrogen. Acid hydrolysis yielded a number of amino acids, including glutamic acid, glycine, α–alanine, valine, leucine, proline, lysine, and arginine, as well as some unidentified compounds; however, TF does not appear to be a low molecular weight straight chain peptide.Although TF contains no iron, it combines readily with ferrous or ferric iron to form reddish-brown complexes with this metal. Activity for A. terregens is shown by certain iron containing complexes as hemin, coprogen, and ferrichrome. On the other hand none is shown by cytochrome or pulcherrimin; however, aspergillic acid, structurally related to the latter, possesses some growth promoting activity for the test organism.

AN ANTIBIOTIC PRODUCED BY MICROCOCCUS EPIDERMIDIS

1950 ◽  
Vol 28e (5) ◽  
pp. 212-216 ◽  
Author(s):  
L. J. Loeb ◽  
A. Moyer ◽  
R. G. E. Murray
Keyword(s):  
Molecular Weight ◽  
Streptococcus Pyogenes ◽  
Water Purification ◽  
Active Substance ◽  
Test Organism ◽  
Chemical Data ◽  
Low Molecular Weight ◽  
Heat Stable ◽  
Wide Range ◽  
Physical And Chemical

A stable antibiotic was produced by a strain of Micrococcus epidermidis that showed a wide range of activity against Gram-positive organisms. A mucoid Streptococcus pyogenes was used as test organism. This strain could be made resistant by being grown in increasing concentrations of antibiotic but the organism reverted to its original susceptibility immediately on transfer to medium without antibiotic. There was no antiluminescent activity when tested on Photobacterium fischeri. The test organism was not lysed by the antibiotic. The active substance was dialyzable, was remarkably heat stable, and was soluble only in water or, providing water was present, in solvents that were completely miscible with water. Purification was successful only to the extent of removing a number of inactive fractions by differential solubilities. The activity was destroyed by trypsin but not by pepsin. The physical and chemical data make it probable that the substance is a polypeptide of low molecular weight.

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

scholarly journals Bridge-therapy with enoxaparin in the preoperative period of endarterectomy

2010 ◽  
Vol 68 (5) ◽  
pp. 775-777
Author(s):  
Jair Leopoldo Raso ◽  
Rogério Zenóbio Darwich ◽  
Francisco de Lucca Jr ◽  
Romeu Valle Santana ◽  
Marco Túlio Tanure ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Mortality Rate ◽  
Prospective Study ◽  
Low Molecular Weight Heparin ◽  
The Other ◽  
Low Molecular Weight ◽  
Preoperative Period ◽  
Safe Strategy ◽  
A Prospective Study ◽  
Bridge Therapy

Cervical clot is one of the complications of endarterectomy. This risk may be higher in patients using aspirin or clopidogrel. On the other hand, stroke may occur if the medication is interrupted before surgery. We carried out a prospective study of 124 endarterectomies in 119 patients in which aspirin or clopidogrel was stopped and a bridge-therapy with enoxaparin was administered preoperatively. There was no case of stroke during the period of the bridge-therapy. One patient developed cervical clot (0.8%) in the fifth postoperative day. Mortality rate in this series was 0.8%. There was no complication directly related to the use of enoxaparin. Bridge-therapy with low molecular weight heparin is a safe strategy for patients elected for endarterectomy

In Vitro Characterization Of Low Molecular Weight Fractions Of Heparin

1981 ◽  
Author(s):  
Jawed Fareed ◽  
Harry L Messmore ◽  
Daniel A Walz ◽  
Jean Choay ◽  
J C Lormeau
Keyword(s):  
Molecular Weight ◽  
The Other ◽  
Low Molecular Weight ◽  
In Vitro Test ◽  
Thrombin Time ◽  
Specific Test ◽  
Platelet Factor ◽  
At Iii ◽  
Heparin Fractions

Numerous extraction, chromatographic (ion exchange, gel, and affinity), chemical and enzymatic degradation methods have been employed to obtain heparin fractions. The present assays to evaluate potency (e.g. pharmacopeial and coagulant) do not truly reflect the antithrombotic properties of these fractions. In addition, the synthetic peptide substrate based assays to measure the anti Xa activity do not correlate with the coagulant anti Xa assays. We have developed an in vitro test battery to evaluate low molecular weight heparin fractions. Porcine mucosal heparin fractions are assayed for anti Xa activity in coagulant and amidolytic assays and the results are expressed as a ratio. The effect of these fractions on coagulant assays such as prothrombin time (PT), partial thromboplastin time (PTT), thrombin time (TT), Stypven time (ST) on freshly prepared normal human plasma (NHP) is determined The retention characteristics of these fractions on platelet factor 4 and AT-III bound sepharose columns were also determined. We have compared the extracted and chemically depolymerized heparin fractions and found that the anti Xa activity doesn’t always correlate with the other parameters studied. The extracted fractions were slightly stronger in the USP assays and showed a biphasic retention on the PF-4 column whereas the chemically depolymerized product showed only one peak. On the other hand, on the AT-III column both fractions showed similar elution patterns. Our studies suggest that heparin and its fractions exhibit differential behavior on various assays and a specific test may not be used as an index of the potency of their antithrombotic effects. Furthermore, the potency of these fractions should be stated on a weight basis when evaluated in the in vivo animal models rather than in terms of a specific test (e.g. anti Xa activity and US Pharmacopeial assays).

scholarly journals Viscoelastic Properties of Unentangled Multicyclic Polystyrenes

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 973 ◽  
Author(s):  
Zhi-Chao Yan ◽  
Md. Hossain ◽  
Michael Monteiro ◽  
Dimitris Vlassopoulos
Keyword(s):  
Molecular Weight ◽  
Shear Viscosity ◽  
Viscoelastic Properties ◽  
Dilution Effect ◽  
The Other ◽  
Low Molecular Weight ◽  
Zero Shear Viscosity ◽  
Rouse Model ◽  
Loop Size ◽  
Linear Chains

We report on the viscoelastic properties of linear, monocyclic, and multicyclic polystyrenes with the same low molecular weight. All polymers investigated were found to exhibit unentangled dynamics. For monocyclic polymers without inner loops, a cyclic-Rouse model complemented by the contribution of unlinked chains (whose fraction was determined experimentally) captured the observed rheological response. On the other hand, multicyclic polymers with inner loops were shown to follow a hierarchical cyclic-Rouse relaxation with the outer loops relaxing first, followed by the inner loop relaxation. The influence of unlinked linear chains was less significant in multicyclic polymers with inner loops. The isofrictional zero-shear viscosity decreased with increasing number of constrained segments on the coupling sites, which was attributed to the decreasing loop size and the dilution effect due to the hierarchical relaxation.

Seasonal changes in the chemical composision of the red alga Hypnea musciformis

1973 ◽  
Vol 24 (3) ◽  
pp. 275
Author(s):  
AF Abdel ◽  
NM Abed ◽  
M Edrees
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Chemical Composition ◽  
Seasonal Changes ◽  
Free Amino ◽  
Glucuronic Acid ◽  
Red Alga ◽  
Low Molecular Weight ◽  
Hypnea Musciformis ◽  
Algal Material

Seasonal changes were observed in the chemical composition of the marine red alga Hypnea musciformis. Lipids, cholesterol, and lanosterol were found as constituents of the algal material. No low-molecular weight carbohydrates were found except small amounts of mannitol. The algal hydrolysate was shown to contain galactose, glucose, and xylose in all seasons and was characterized by a high content of glucuronic acid and its lactone in February. Definite seasonal variations were found in the patterns of free amino acids and of amino acid compositions of proteins.

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.

Stimulation of Mesothelial Cells Proliferation by Endogenous Growth Factor(s)

1991 ◽  
Vol 11 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Andrzej Breborowicz ◽  
Helen Rodela ◽  
Jim Pagiamtzis ◽  
Dimitrios G. Oreopoulos
Keyword(s):  
Growth Factor ◽  
Conditioned Medium ◽  
Endogenous Growth ◽  
Mesothelial Cells ◽  
The Other ◽  
Heat Stable ◽  
Factor Production ◽  
Low Glucose ◽  
Growth Factor Production ◽  
Growth Promoting

We have attempted to determine whether human mesothelial cells (MC) have the power to influence their own proliferation. A serum -free medium was conditioned with the mesothelial monolayer for 24 hours and then applied to proliferating MC. Conditioned medium increased proliferation rate of MC. When the medium was heated at 60°C for 60 minutes, the growth-promoting activity of the conditioned medium decreased by 50%, suggesting that MC produce at least 2 growth factors, 1 heat-Iabile and the other heat-stable. When MC were exposed continuously to a medium containing 90 mM glucose growth factor, production was decreased by 35%. However, when the cells were exposed to glucose only on alternate days, growth-factor production was similar to that in the control medium. On the other hand, MC exposed continuously for 10 days to 90 mM of glucose exhibited a weaker response to endogenous growth factor, even in a normotonic medium with low glucose concentration. Our results suggest that MC syn thesize factor(s), which stimulate their own proliferation, and that high glucose concentrations interfere with this production and the subsequent action of growth factor.

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