Determinants of the Formation and Activity of Factor V-phospholipid Complexes II. Molecular Properties of the Complexes

1975 ◽  
Vol 34 (01) ◽  
pp. 271-284 ◽  
Author(s):  
Carol L Kandall ◽  
Stephen B Shohet ◽  
T. K Akinbami ◽  
Robert W Colman
Keyword(s):  
Buoyant Density ◽  
Fold Increase ◽  
Sucrose Density Gradient ◽  
Phosphatidyl Serine ◽  
Active Species ◽  
Intrinsic Activity ◽  
Factor V ◽  
High Concentrations ◽  
The Stability ◽  
Very High

SummaryThe stability, buoyancy, and intrinsic activity of factor V-phospholipid complexes were investigated.The decay of factor V activity in the absence of phospholipid followed first order kinetics; however, in the presence of several phospholipids a biphasic decay curve was observed. The addition of phosphatidylethanolamine to factor V produced only a small loss of activity in the first 2 minutes but decreased the subsequent rate of inactivation fourfold. A PE-factor V complex with a low bouyant density was separated from uncomplexed factor V by sucrose density ultracentrifugation. The association constant for this complex was 5 × 106 M-1 with approximately 2 moles of factor V bound per mole of lipid micelle. The isolated complex was capable of increasing prothrombin conversion 10-fold without additional phospholipid. A still lighter complex increased the rate of prothrombin conversion 18-fold.Phosphatidyl serine produced a concentration-dependent loss of up to 95% of the factor V activity in the first 2 minutes. After ultracentrifugation on a sucrose density gradient, a PS-factor V complex of increased density was detected. This complex failed to accelerate prothrombin conversion in the intrinsic two-stage assay.Except at very high concentrations, phosphatidylcholine did not alter the kinetics of inactivation of factor V. A factor V-phosphatidylcholine complex could not be detected after ultracentrifugation.When added to factor V, cardiolipin (200 μg/ml), produced a rapid 50% decline in activity with a subsequent three-fold increase in the rate of inactivation. No activity was recovered after ultracentrifugation of factor V in the presence of cardiolipin.Saturated phosphatidylethanolamine produced a concentration dependent initial loss of activity, but only a minimal increase in the subsequent rate of inactivation. At 200 μg/ml almost no light complex was detected after ultracentrifugation, but at 800 μg/ml a light complex was observed. This behavior corresponds to the ability of saturated phosphatidylethanolamine to accelerate prothrombin conversion only at very high concentrations.Thus, phospholipids combine with factor V to form complexes which differ in their ability to accelerate prothrombin conversion. The most active species are stable lipoprotein complexes of lower buoyant density than factor V.

Self-association, cooperativity and supercooperativity of oxygen binding by hemoglobins.

1998 ◽  
Vol 201 (8) ◽  
pp. 1073-1084 ◽  
Author(s):  
A F Riggs
Keyword(s):  
Muscle Tissue ◽  
Buoyant Density ◽  
Fold Increase ◽  
Heme Iron ◽  
Common Mechanism ◽  
Oxygen Binding ◽  
Hypoxic Environment ◽  
Self Association ◽  
The Stability ◽  
O2 Binding

Cooperative ligand binding by tetrameric vertebrate hemoglobins (Hbs) makes possible the delivery of oxygen at higher pressures than would otherwise occur. This cooperativity depends on changes in dimer-dimer interactions within the tetramer and is reflected in a 50 000-fold increase in the tetramer-dimer dissociation constant in human Hb upon oxygenation at pH 7.4, from approximately 2x10(-11)mol l-1 to approximately 10(-6)mol l-1. Hbs that undergo such ligand-dependent changes in association are widespread in non-vertebrates, where the mechanisms are very different from those in vertebrates. Oligomeric Hbs have been identified in organisms in five phyla (molluscs, echinoderms, annelids, phoronids and chordates) that dissociate to subunits upon oxidation of the heme iron and reassociate with the binding of ferric iron ligands such as CN-, N3- or NO2-. Thus, the valence and ligand state of the heme iron control the stability of a critical subunit interface. The broad distribution of this phenomenon suggests a common mechanism of communication between heme and interface that may be almost universal among non-vertebrate Hbs. This interaction may be similar to that known for the homodimeric Hb of the mollusc Scapharca inaequivalvis. Although muscle tissue Hbs or myoglobins (Mbs) are usually monomeric, with non-cooperative O2 binding, the radular muscles of gastropod molluscs and chitons have homodimeric Mbs that bind O2 cooperatively. Cooperative non-muscle tissue Hbs have also been identified. These include the neural Hb of the nemertean worm Cerebratulus lacteus and the Hb of the diving beetle Anisops assimilis, which exhibit deoxygenation-dependent self-association of monomers that is associated with high Hill coefficients. Calculations suggest that the 2-3 mmol l-1 concentration of Hb on a heme basis in the brain of Cerebratulus should substantially extend the time as an active predator in an anaerobic or hypoxic environment. Oxygen from the Hb of Anisops is delivered to a gas bubble and thereby controls the buoyant density. Many Hbs of amphibians, reptiles, birds and some embryonic mammals exhibit a further 'supercooperativity' of O2 binding which depends on reversible deoxygenation-dependent tetramer-tetramer association to form an assemblage with a very low affinity for O2. This phenomenon results in steeper O2-binding curves than exhibited by tetramers alone. The increased cooperativity should result in an increase in the amount of O2 delivered to the tissues and should be especially valuable for avian flight muscles.

scholarly journals The control of ribonucleic acid synthesis in bacteria. The synthesis and stability of ribonucleic acids in relaxed and stringent amino acid auxotrophs of Escherichia coli

1972 ◽  
Vol 128 (5) ◽  
pp. 1007-1020 ◽  
Author(s):  
W. J. H. Gray ◽  
J. E. M. Midgley
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Heterogeneous Material ◽  
Acid Synthesis ◽  
Sucrose Density Gradient ◽  
23S Rrna ◽  
Ribonucleic Acids ◽  
Mrna Content ◽  
High Concentrations ◽  
The Stability

The biosynthesis and stability of various RNA fractions was studied in RCstr and RCrel multiple amino acid auxotrophs of Escherichia coli. In conditions of amino acid deprivation, RCstr mutants were labelled with exogenous nucleotide bases at less than 1% of the rate found in cultures growing normally in supplemented media. Studies by DNA–RNA hybridization and by other methods showed that, during a period of amino acid withdrawal, not more than 60–70% of the labelled RNA formed in RCstr mutants had the characteristics of mRNA. Evidence was obtained for some degradation of newly formed 16S and 23S rRNA species to heterogeneous material of lower molecular weight. This led to overestimations of the mRNA content of rapidly labelled RNA from such methods as simple examination of sucrose-density-gradient profiles. In RCrel strains the absolute and relative rates of synthesis of the various RNA fractions were not greatly affected. However, the stability of about half of the mRNA fraction was increased in RCrel strains during amino acid starvation, giving kinetics of mRNA labelling and turnover that were identical with those found in either RCstr or RCrel strains inhibited by high concentrations of chloramphenicol. Coincidence hybridization techniques showed that the mRNA content of amino acid-starved RCstr auxotrophs was unchanged from that found in normally growing cells. In contrast, RCrel strains deprived of amino acids increased their mRNA content about threefold. In such cultures the mRNA content of accumulating newly formed RNA was a constant 16% by wt.

scholarly journals Synergism Between Phosphine (PH3) and Carbon Dioxide (CO2): Implications for Managing PH3 Resistance in Rusty Grain Beetle (Laemophloeidae: Coleoptera)

2020 ◽  
Vol 113 (4) ◽  
pp. 1999-2006
Author(s):  
Myrna Constantin ◽  
Rajeswaran Jagadeesan ◽  
Kerri Chandra ◽  
Paul Ebert ◽  
Manoj K Nayak
Keyword(s):  
Carbon Dioxide ◽  
Reference Strain ◽  
Fold Increase ◽  
Stored Grain ◽  
Response Data ◽  
Alternative Approach ◽  
Mortality Response ◽  
High Concentrations ◽  
Carbon Dioxide Co2 ◽  
Very High

Abstract Strong resistance to phosphine (PH3) in the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Laemophloeidae: Coleoptera) poses a serious risk to stored-grain biosecurity. Resistant populations hold risk of surviving in PH3 fumigation, particularly in storage structure that limits achieving very high concentrations of PH3, demanding the need for alternative fumigation strategies. Cofumigation with PH3 and carbon dioxide (CO2) is one alternative approach that has the potential to be used widely. CO2 fumigation of adults of strongly PH3-resistant reference strain of C. ferrugineus, for 48 h, showed that the effective concentration (LC50) of CO2 was 30.99%. This 30% level of CO2 in combination with PH3 decreased the LC50 of PH3 from 6.7 mg/liter to 0.84 mg/liter, an eightfold increase in PH3 efficacy relative to PH3 fumigation in normal air. The LC99.9 decreased from 16.2 mg/liter to 5.8 mg/liter, a 2.8-fold increase in PH3 efficacy. Comparison of mortality response data of PH3 alone and the PH3 + CO2 mixture confirmed that CO2 enhances the toxicity of PH3 synergistically in addition to exerting its own toxicity. These results were validated against three independently field-derived strains of strongly resistant C. ferrugineus that confirmed that observed enhancement in toxicity with the PH3 + CO2 mixture was consistent, irrespective of differences in resistance phenotypes and inherent tolerance levels. Results of the current study provide further opportunities to develop new commercially viable strategy to control strongly PH3-resistant C. ferrugineus.

Human Blood Serum Rich in Factor V

1970 ◽  
Vol 24 (03/04) ◽  
pp. 334-337 ◽  
Author(s):  
R Honorato
Keyword(s):  
Blood Serum ◽  
Human Serum ◽  
Human Blood ◽  
Human Blood Serum ◽  
Factor V ◽  
The Stability

Summary1. A technique to obtain human serum rich in factor V is described.2. Calcium increases the stability of factor V in the serum.

Methods for the Concentration of Bovine Ac-Globulin (Factor V)

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Room Temperature ◽  
Barium Carbonate ◽  
Deae Cellulose ◽  
Reducing Agents ◽  
Factor V ◽  
Isoelectric Precipitation ◽  
Stabilizing Agent ◽  
Bovine Plasma ◽  
The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

scholarly journals Halogenated Volatile Organic Compounds in Water Samples and Inorganic Elements Levels in Ores for Characterizing a High Anthropogenic Polluted Area in the Northern Latium Region (Italy)

2021 ◽  
Vol 18 (4) ◽  
pp. 1628
Author(s):  
Mario Vincenzo Russo ◽  
Ivan Notardonato ◽  
Alberto Rosada ◽  
Giuseppe Ianiri ◽  
Pasquale Avino
Keyword(s):  
Organic Compounds ◽  
Mean Value ◽  
Greenhouse Crops ◽  
River Waters ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
High Concentrations ◽  
Very High ◽  
Inorganic Fraction

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid–liquid extraction and static headspace) followed by gas chromatography–electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L−1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g−1), antimony (77.7 µg g−1), strontium (12,039 µg g−1) and zinc (103 µg g−1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g−1): the levels found in this paper (ranging between 1 and 5100 µg g−1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.

scholarly journals Glucose-Responsive Gene Delivery at Physiological pH through Tertiary-Amine Stabilized Boronate-PVA Particles Synthesized by One-Pot Reaction

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 62
Author(s):  
Mangesh Morey ◽  
Akshay Srivastava ◽  
Abhay Pandit
Keyword(s):  
Gene Delivery ◽  
Fold Increase ◽  
Nonviral Gene Delivery ◽  
Luciferase Reporter ◽  
Hydrodynamic Diameter ◽  
Luciferase Reporter Gene ◽  
One Pot ◽  
Gaussia Luciferase ◽  
Nih3t3 Cells ◽  
The Stability

We report a physiologically stable and cytocompatible glucose-responsive nonviral gene delivery system made up of boronate functionalized polymeric material. Herein, we utilize boronate cis-diol interactions to develop a glucose-responsive submicron particle (SMP) system. The stability of the boronate interaction at a physiological pH was achieved by copolymerization of dimethyl aminoethyl methacrylate (DMAEMA) with acrylamidophenylboronic acid (AAPBA) and the formation of a complex with polyvinylalcohol (PVA) which is governed by cis-diol interactions. The shift in hydrodynamic diameter of SMPs was observed and correlated with increasing glucose concentrations at a physiological pH. Optimal transfection was observed for a 5 µg dose of the gaussia luciferase reporter gene in NIH3T3 cells without any adverse effect on cellular viability. The destabilization of the AAPBA–PVA complex by interacting with glucose allowed the release of encapsulated bovine serum albumin (BSA) in a glucose-responsive manner. In total, 95% of BSA was released from SMPs at a 50 mM glucose concentration after 72 h. A two-fold increase in transfection was observed in 50 mM glucose compared to that of 10 mM glucose.

THE SELECTIVE PROTEOLYTIC ENZYME INHIBITORY ACTION OF BENZETHONIUM CHLORIDE

1960 ◽  
Vol 38 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Ivan T. Beck ◽  
E. Pinter ◽  
R. D. McKenna ◽  
H. Griff
Keyword(s):  
Subcutaneous Injection ◽  
Proteolytic Enzyme ◽  
Inhibitory Action ◽  
Hemorrhagic Pancreatitis ◽  
Benzethonium Chloride ◽  
Tryptic Activity ◽  
High Concentrations ◽  
Acute Hemorrhagic Pancreatitis ◽  
Very High

Acute hemorrhagic pancreatitis in humans is thought to be perpetuated by the autolytic processes catalyzed by trypsin and lipase. This study is an integral part of our search for trypsin and lipase inhibitors to be used in the treatment of this disease.Benzethonium chloride was found to inhibit tryptic activity in vitro. The proteolytic activity of rabbit's serum was inhibited, and the inhibition was most pronounced 6 to 12 hours after the subcutaneous injection of the compound. Fibrinolysin was also inhibited in vitro but benzethonium chloride had no inhibitory action on chymotrypsin, pepsin, or lipase.Serum proteins in vitro were precipitated only with very high concentrations of the compound. No significant protein changes were observed in sera of rabbits after the subcutaneous injection of the compound.

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