scholarly journals ON THE MECHANISM OF OPSONIN AND BACTERIOTROPIN ACTION

1930 ◽  
Vol 13 (6) ◽  
pp. 669-681 ◽  
Author(s):  
Morton McCutcheon ◽  
Stuart Mudd ◽  
Max Strumia ◽  
Balduin Lucké
Keyword(s):  
Surface Properties ◽  
Isoelectric Point ◽  
Immune Serum ◽  
Isoelectric Points ◽  
Alkaline Side

Sensitization with increasing concentrations of homologous immune serum shifts the isoelectric point of the antigens studied progressively to the alkaline side. Antigens maximally sensitized with rabbit sera have shown isoelectric points of pH 5.6 to 5.8. The globulins precipitated or salted out of the same immune sera have been isoelectric at pH 5.1 to 5.2. The combination of antigen with antibody depends of course upon specific affinities; the surface properties of the sensitized antigen, agglutination and phagocytosis depend primarily upon the properties of the sensitizing serum substances combined with and deposited on the antigen surface.

scholarly journals THE ISOELECTRIC POINT OF RED BLOOD CELLS AND ITS RELATION TO AGGLUTINATION

1921 ◽  
Vol 3 (3) ◽  
pp. 309-323 ◽  
Author(s):  
Calvin B. Coulter
Keyword(s):  
Red Blood Cells ◽  
Isoelectric Point ◽  
Blood Cells ◽  
Inorganic Ions ◽  
Immune Serum ◽  
Ion Concentration ◽  
Normal Cells ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Chlorine Ions

1. The movement of normal and sensitized red blood cells in the electric field is a function of the hydrogen ion concentration. The isoelectric point, at which no movement occurs, corresponds with pH 4.6. 2. On the alkaline side of the isoelectric point the charge carried is negative and increases with the alkalinity. On the acid side the charge is positive and increases with the acidity. 3. On the alkaline side at least the charge carried by sensitized cells is smaller and increases less rapidly with the alkalinity than the charge of normal cells. 4. Both normal and sensitized cells combine chemically with inorganic ions, and the isoelectric point is a turning point for this chemical behavior. On the acid side the cells combine with the hydrogen and chlorine ions, and in much larger amount than on the alkaline side; on the alkaline side the cells combine with a cation (Ba), and in larger amount than on the acid side. This behavior corresponds with that found by Loeb for gelatin. 5. The optimum for agglutination of normal cells is at pH 4.75, so that at this point the cells exist most nearly pure, or least combined with anion and cation. 6. The optimum for agglutination of sensitized cells is at pH 5.3. This point is probably connected with the optimum for flocculation of the immune serum body.

scholarly journals A PHYSICAL-CHEMICAL DIFFERENCE IN ANTIBODIES AGAINST THE S AND R VARIANTS OF A SINGLE BACTERIAL STRAIN

1935 ◽  
Vol 18 (5) ◽  
pp. 615-625 ◽  
Author(s):  
Eleanore W. Joffe
Keyword(s):  
Immune Serum ◽  
Chemical Difference ◽  
Hyperimmune Serum ◽  
Long Period ◽  
Electrophoretic Mobilities ◽  
Physical Chemical ◽  
Isoelectric Points ◽  
Agglutination Titer ◽  
Alkaline Side ◽  
Heterologous Serum

1. Rabbits were immunized with Bact. typhosum 0 901 S and 0 901 R, over a long period. Homologous and heterologous strains were sensitized with sera obtained from weekly bleedings. Agglutination titer was recorded, and the isoelectric points of the bacteria maximally sensitized were determined. 2. 0 901 S maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering a range of pH 4.8 to 5.5. 3. Strain 0 901 R maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering the range of pH 5.0 to 5.9. 4. Both 0 901 S and 0 901 R maximally sensitized with heterologous serum had isoelectric points lower than when sensitized with homologous serum. 5. The isoelectric points of both forms sensitized with increasing concentrations of homologous immune serum were determined. Increasing concentrations of homologous immune serum shifted the isoelectric point of 0 901 R from less than 2.2 for the unsensitized bacteria progressively to the alkaline side until the maximum values previously mentioned were reached. Increasing concentrations of homologous immune serum conferred upon 0 901 S isoelectric points which became only slightly more alkaline in maximal sensitization. 6. The electrophoretic mobilities of 0 901 S and 0 901 R, in each case maximally sensitized with homologous hyperimmune serum, were found to differ significantly over the whole range of pH studied.

scholarly journals Delineating the Specific Influence of Virus Isoelectric Point and Size on Virus Adsorption and Transport through Sandy Soils

1998 ◽  
Vol 64 (2) ◽  
pp. 405-410 ◽  
Author(s):  
Scot E. Dowd ◽  
Suresh D. Pillai ◽  
Sookyun Wang ◽  
M. Yavuz Corapcioglu
Keyword(s):  
Isoelectric Point ◽  
Transport Model ◽  
Virus Particles ◽  
Transport Studies ◽  
Viral Transport ◽  
Virus Adsorption ◽  
Isoelectric Points ◽  
Kinetic Sorption ◽  
Viral Adsorption ◽  
Specific Influence

ABSTRACT Many of the factors controlling viral transport and survival within the subsurface are still poorly understood. In order to identify the precise influence of viral isoelectric point on viral adsorption onto aquifer sediment material, we employed five different spherical bacteriophages (MS2, PRD1, Qβ, φX174, and PM2) having differing isoelectric points (pI 3.9, 4.2, 5.3, 6.6, and 7.3 respectively) in laboratory viral transport studies. We employed conventional batch flowthrough columns, as well as a novel continuously recirculating column, in these studies. In a 0.78-m batch flowthrough column, the smaller phages (MS2, φX174, and Qβ), which had similar diameters, exhibited maximum effluent concentration/initial concentration values that correlated exactly with their isoelectric points. In the continuously recirculating column, viral adsorption was negatively correlated with the isoelectric points of the viruses. A model of virus migration in the soil columns was created by using a one-dimensional transport model in which kinetic sorption was used. The data suggest that the isoelectric point of a virus is the predetermining factor controlling viral adsorption within aquifers. The data also suggest that when virus particles are more than 60 nm in diameter, viral dimensions become the overriding factor.

Differences in Transcription and Translation of Long and Short GSα, the Stimulatory G-Protein, in Human Atrium

1995 ◽  
Vol 89 (5) ◽  
pp. 487-495 ◽  
Author(s):  
M. Susan Monteith ◽  
Tao Wang ◽  
Morris J. Brown
Keyword(s):  
Cyclic Amp ◽  
Isoelectric Point ◽  
Right Atrial ◽  
Two Dimensional ◽  
Human Atrium ◽  
Post Translational Modification ◽  
Two Dimensional Gel Electrophoresis ◽  
Significant Difference ◽  
Isoelectric Points

1. We have previously reported the relative mRNA and protein level of the long and short splice variants of Gsα (GsαL and GsαS) in human atrium. We have now measured the relative proportions of the serine+ and serine− variants of GsαL and GsαS in human atrium, and assessed, indirectly, whether their differential expression may (i) regulate Gsα phosphorylation, and (ii) be regulated by atrial cyclic AMP levels. 2. The serine+ and serine− variants of GsαL and GsαS were estimated by single nucleotide primer extension in 36 right atrial strips of which half were from β-adrenoceptor-blocked patients. The ratio of serine+ to serine− variants was 0.06 ± 0.12 for GsαL, compared with 8.04 ± 12.16 for GsαS (P < 0.001). 3. Isoelectric points of GsαL and GsαS in the atria of four β-adrenoceptor-blocked and four non-β-adrenoceptor-blocked patients were estimated by two-dimensional gel electrophoresis. Two-dimensional gel analysis gave a consistent pattern with several spots for both GsαL and GsαS; however, the isoelectric points of GsαS were more acid (5.18 ± 0.24) than those of GsαL (5.87 ± 0.17, P < 0.001). 4. No significant difference in either the serine variants or isoelectric point value was observed between β-adrenoceptor-blocked and non-β-adrenoceptor-blocked patients. 5. In conclusion, all four Gsα variants were expressed in human atrium, but GsαL is almost entirely of the serine− form. GsαS has a more acidic isoelectric point than GsαL, indicating a possible post-translational modification. The lack of difference in our results between β-adrenoceptor-blocked and non-β-adrenoceptor-blocked patients suggests indirectly that cyclic AMP is an unlikely candidate for regulating splicing or post-translational modification of Gsα in vivo.

scholarly journals AMPHOTERIC COLLOIDS

1918 ◽  
Vol 1 (2) ◽  
pp. 237-254 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Isoelectric Point ◽  
Water Solubility ◽  
Biological Significance ◽  
Volumetric Analysis ◽  
The Body ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Sharp Drop ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side

1. It is shown by volumetric analysis that on the alkaline side from its isoelectric point gelatin combines with cations only, but not with anions; that on the more acid side from its isoelectric point it combines only with anions but not with cations; and that at the isoelectric point, pH = 4.7, it combines with neither anion nor cation. This confirms our statement made in a previous paper that gelatin can exist only as an anion on the alkaline side from its isoelectric point and only as a cation on the more acid side of its isoelectric point, and practically as neither anion nor cation at the isoelectric point. 2. Since at the isoelectric point gelatin (and probably amphoteric colloids generally) must give off any ion with which it was combined, the simplest method of obtaining amphoteric colloids approximately free from ionogenic impurities would seem to consist in bringing them to the hydrogen ion concentration characteristic of their isoelectric point (i.e., at which they migrate neither to the cathode nor anode of an electric field). 3. It is shown by volumetric analysis that when gelatin is in combination with a monovalent ion (Ag, Br, CNS), the curve representing the amount of ion-gelatin formed is approximately parallel to the curve for swelling, osmotic pressure, and viscosity. This fact proves that the influence of ions upon these properties is determined by the chemical or stoichiometrical and not by the "colloidal" condition of gelatin. 4. The sharp drop of these curves at the isoelectric point finds its explanation in an equal drop of the water solubility of pure gelatin, which is proved by the formation of a precipitate. It is not yet possible to state whether this drop of the solubility is merely due to lack of ionization of the gelatin or also to the formation of an insoluble tautomeric or polymeric compound of gelatin at the isoelectric point. 5. On account of this sudden drop slight changes in the hydrogen ion concentration have a considerably greater chemical and physical effect in the region of the isoelectric point than at some distance from this point. This fact may be of biological significance since a number of amphoteric colloids in the body seem to have their isoelectric point inside the range of the normal variation of the hydrogen ion concentration of blood, lymph, or cell sap. 6. Our experiments show that while a slight change in the hydrogen ion concentration increases the water solubility of gelatin near the isoelectric point, no increase in the solubility can be produced by treating gelatin at the isoelectric point with any other kind of monovalent or polyvalent ion; a fact apparently not in harmony with the adsorption theory of colloids, but in harmony with a chemical conception of proteins.

scholarly journals Isoelectric points of erabutoxins and monoacyl derivatives of erabutoxin b. Estimation of the pK values of amino groups in erabutoxins by using isoelectric-focusing data

1982 ◽  
Vol 203 (2) ◽  
pp. 427-433 ◽  
Author(s):  
N UI ◽  
C Takasaki ◽  
N Tamiya
Keyword(s):  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Amino Group ◽  
Amino Groups ◽  
Sea Snake ◽  
Isoelectric Points ◽  
Point Data ◽  
Laticauda Semifasciata ◽  
Erabutoxin B ◽  
Derivatives Of

The isoelectric points of erabutoxins a, b and c, neurotoxic proteins of a sea snake, Laticauda semifasciata, were determined by density-gradient isoelectric focusing. The same measurement was also made with monoacyl derivatives of erabutoxin b, in which each one of all amino groups had been either acetylated or propionylated. Erabutoxins a and b showed the same isoelectric point at pH 9.68. The values for [1-N alpha-acetyl-arginine]-, [15-N6-acetyl-lysine]-, [27-N6-acetyl-lysine]-, [47-N6-propionyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b were at pH 9.52, 9.31, 9.45, 9.22 and 9.09 respectively, being definitely different from each other and lower than the value for the unmodified molecule. The isoelectric point of erabutoxin c, which is [51-asparagine]-erabutoxin b, was the same as that of [51-N6-acetyl-lysine]erabutoxin b. Assuming that no change in pK occurs on monoacylation, the pK values of amino groups in erabutoxin b were calculated from the isoelectric-point data. It is indicated that the pK values of zeta-amino groups differ markedly from each other and that the value of alpha-amino group is anomalously high.

Adhesion of Acidithiobacillus Caldus and Leptospirillum Ferriphilum on Pyrite and their Effect on Surface Properties of Sulfide Minerals

2009 ◽  
Vol 71-73 ◽  
pp. 449-452
Author(s):  
G. Gu ◽  
Li Jun Su ◽  
Guan Zhou Qiu ◽  
Y. Hu
Keyword(s):  
Surface Properties ◽  
Isoelectric Point ◽  
Sulfide Minerals ◽  
Ferrous Ion ◽  
Bacterial Cells ◽  
Leptospirillum Ferriphilum ◽  
Acidithiobacillus Caldus ◽  
Ft Ir ◽  
Bacterial Adsorption ◽  
Strong Ability

Acidithiobacillus caldus and Leptospirillum ferriphilum cells grown in different energy substances (ferrous ion, sulfur and pyrite) were used. The adhesion of A. caldus and L. ferriphilum cells on pyrite and their effect on pyrite surface properties were studied by adsorption, zeta-potential and FT-IR methods, and the corrosion images of pyrite interaction with bacteria were examined using atomic force microscopy. Research showed that pyrite isoelectric point (IEP) after interaction with bacterial cells shifted towards cells isoelectric point, and the shift degree in case of interaction with A. caldus was observed to be much more pronounced than for interaction with L. ferriphilum, which can be due to higher affinity of A. caldus towards pyrite. The FT-IR spectra of pyrite treated with bacterial cells revealed the presence of the cell functional groups signifying cells adsorption. Although the adsorption density of A. caldus on pyrite was higher than that of L. ferriphilum, L. ferriphilum with strong ability to oxidize ferrous ion showed better leaching efficiency than A. caldus with strong ability to oxidize sulfur for pyrite leaching. The results demonstrated that more important of indirect action (L. ferriphilum) than direct action (A. caldus) on pyrite.Introduction Bacterial adsorption to minerals is an initial step in bacterial leaching for metal recovery [1]. It has been reported that bacterial adhesion is dependent not only on the biochemical properties of the organism but also on the interfacial properties of the various interfaces existing in a bioleaching system[2].The bacteria-mineral interactions result in the changes of their surface properties. The elucidation of their alternate will be beneficial for bioleaching processes. Both Acidithiobacillus caldus and Leptospirillum ferriphilum are known for their ability to inhabit acidic environments and derive energy from oxidation of inorganic substances with natural occurrence in ore deposits and acid mine drainage and high affinity towards sulfide minerals [3-5]. In this work, the alterations of surface properties of pyrite after interaction with L. ferriphilum and A. caldus are studied, and the changes in surface properties caused by bacterial adsorption are discussed with reference to bioleaching behavior of pyrite.

scholarly journals ISOELECTRIC POINTS FOR THE MYCELIUM OF FUNGI

1924 ◽  
Vol 6 (3) ◽  
pp. 259-271 ◽  
Author(s):  
William J. Robbins
Keyword(s):  
Phosphoric Acid ◽  
Sodium Hydroxide ◽  
Isoelectric Point ◽  
Dry Matter ◽  
Colony Growth ◽  
Potato Dextrose Broth ◽  
Rhizopus Nigricans ◽  
Basic Dyes ◽  
Isoelectric Points ◽  
Initial Ph

1. Mycelium of Rhizopus nigricans when stained with certain acid and basic dyes and washed with buffer mixtures of 0.1 M phosphoric acid and sodium hydroxide responded much like an amphoteric colloid with an isoelectric point near pH 5.0. 2. When grown on potato dextrose agar the reaction of which was varied with phosphoric acid the extent of colony growth of Rhizopus nigricans plotted against the initial Sörensen value of the agar produced a double maximum curve with the minimum between the two maxima at initial pH 5.2. 3. When grown in potato dextrose broth the reaction of which was varied with phosphoric acid the dry matter produced by Rhizopus nigricans plotted against the Sörensen value of the broth produced a double maximum curve with the minimum between the two maxima at initial pH 5.2 or average pH 4.9. 4. Mycelium of Rhizopus nigricans placed in buffer mixtures of 0.01 M phosphoric acid and sodium hydroxide of pH 4.1 to 6.3, changed the reaction in most cases toward greater alkalinity. 5. Mycelium of Fusarium lycopersici stained with certain acid and basic dyes and washed with buffer mixtures of 0.1 M phosphoric acid and sodium hydroxide responded much like an amphoteric colloid with an isoelectric point near pH 5.5.

Isoelectric focusing of the human TSH receptor A subunit

1986 ◽  
Vol 6 (7) ◽  
pp. 685-689 ◽  
Author(s):  
F. A. Hashim ◽  
E. Davies Jones ◽  
R. D. Howells ◽  
B. Rees Smith
Keyword(s):  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Water Soluble ◽  
Tsh Receptor ◽  
Isoelectric Points ◽  
A Subunit ◽  
Receptor Antibodies ◽  
Tsh Receptor Antibodies ◽  
Charge Interactions

The water soluble A subunit of the human TSH receptor has been shown to have an isoelectric point of 5. As both TSH and TSH receptor antibodies have isoelectric points in the region of 8–10, charge-charge interactions must be of major importance in the binding of hormone or antibody to the TSH receptor A subunit.

scholarly journals THE ISOELECTRIC POINTS OF THE PROTEINS IN CERTAIN VEGETABLE JUICES

1919 ◽  
Vol 2 (2) ◽  
pp. 145-160 ◽  
Author(s):  
Edwin J. Cohn ◽  
Joseph Gross ◽  
Omer C. Johnson
Keyword(s):  
Electric Field ◽  
Isoelectric Point ◽  
The State ◽  
Hydrogen Ion ◽  
Tomato Juice ◽  
Ion Concentration ◽  
Carrot Juice ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Isoelectric Points

The state in which a protein substance exists depends upon the nature of its combination with acids or bases and is changed by change in the protein compound. The nature of the compound of a protein that exists at any hydrogen ion concentration can be ascertained if the isoelectric point of the protein is known. Accordingly information regarding the isoelectric points of vegetable proteins is of importance for operations in which it may be desirable to change the state of protein substances, as in the dehydration of vegetables. The Protein in Potato Juice.—The hydrogen ion concentration of the filtered juice of the potato is in the neighborhood of 10–7N. Such juice contains the globulin tuberin to the extent of from 1 to 2 per cent. The character of the compound of tuberin that exists in nature was suggested by its anodic migration in an electric field. The addition of acid to potato juice dissociated this compound and liberated tuberin at its isoelectric point. The isoelectric point of tuberin coincided with a slightly lower hydrogen ion concentration than 10–4N. At that reaction it existed most nearly uncombined. The flow of current during cataphoresis was greatest in the neighborhood of the isoelectric point. This evidence supplements that of the direction of the migration of tuberin, since it also suggests the existence of the greatest number of uncombined ions near this point. At acidities greater than the isoelectric point tuberin combined with acid. The compound that was formed contained nearly three times as much acid as was needed to dissociate the tuberin compound that existed in nature. At such acidities tuberin migrated to the cathode. Though never completely precipitated tuberin was least soluble in the juice of the potato in the neighborhood of its isoelectric point. Both the compounds of tuberin with acids and with bases were more soluble in the juice than was uncombined tuberin. The nature of the slight precipitate that separated when potato juice was made slightly alkaline was not determined. The Protein in Carrot Juice.—The isoelectric point of the protein in carrot juice coincided with that of tuberin. Remarkably similar also were the properties of carrot juice and the juice of the potato. Existing in nature at nearly the same reaction they combined with acids and bases to nearly the same extent and showed minima in solubility at the same hydrogen ion concentrations. The greatest difference in behavior concerned the alkaline precipitate which, in the carrot, was nearly as great as the acid precipitate. The Protein in Tomato Juice.—The protein of the tomato existed in a precipitated form near its isoelectric point. Accordingly it was not present to any extent in filtered tomato juice. If, however, the considerable acidity at which the tomato exists was neutralized the protein dissolved and was filterable. It then migrated to the anode in an electric field. The addition of sufficient acid to make the hydrogen ion concentration slightly greater than 10–5N again precipitated the protein at its isoelectric point. At greater acidities migration was cathodic.

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