Variation In Electrophoretic Mobility Research Articles

The antigenic pattern of the developing brain of the zebrafish, Brachydanio rerio

AbstractDevelopmental stages, from eight cells to 28 days post‐hatching, of the zebrafish, Brachydanio rerio, were analysed by immunoelectrophoresis with unabsorbed and absorbed rabbit antiserum to adult zebrafish brain. From the earliest embryonic stage to the oldest post‐hatching stage tested, a developing antigenic pattern was recognizable. Six antigens, found to be consistently present in all stages, exhibited no observable variation in electrophoretic mobility or diffusion rates. Of four other antigens present in the earliest stage analysed, one appeared intermittently throughout subsequent developmental stages. Three antigens appeared consistently, but showed variations in electrophoretic mobility at different stages. Fourteen ‐antigens, two of which were transitory, appeared during development, adding to the complexity of the antigenic pattern. Including all stable and variant forms of antigens, a total of 30 antigens was detected from the earliest embryonic stage to the oldest post‐hatching stage tested.

Studies on Two Physiological Forms of the Human Retinol-binding Protein Differing in Vitamin A and Arginine Content

Abstract The human retinol-binding protein (RBP) is shown to exist in two main physiological forms each of which displays electrophoretic heterogeneity. Only one of the two RBP components contains vitamin A. The retinol-containing RBP species is under physiological conditions firmly bound to thyroxine-binding prealbumin. The protein complex thereby formed is the actual vitamin A carrier normally encountered in plasma. The vitamin A-free form of RBP is unable to bind prealbumin. The difference in the affinity of the two RBP species for prealbumin made it possible to separate them by chromatography on a Sepharose gel to which prealbumin had been covalently attached. Differences in conformation between the two RBP components were established by physical-chemical, chemical, and immunological techniques. On polyacrylamide gel electrophoresis both species of RBP exhibited multiple bands. The studies revealed that the variations in electrophoretic mobility could be ascribed to differences in the content of vitamin A, in the number of amide groups, and in the sequence of the COOH-terminal amino acid residues. Hence, it was found that the vitamin A-containing form of RBP had an additional residue of arginine compared to the form lacking the vitamin. This result, obtained by amino acid analysis, was confirmed by peptide mapping, which revealed an arginine-stainable spot present only in the vitamin A-containing species. The COOH-terminal amino acid sequences in the two RBP species were -Lys-Arg-OH and -Lys-OH, respectively. The loss of 1 amino acid residue from the vitamin A-free species obviously causes a conformational change which is not compatible with the binding to prealbumin. Vitamin A per se is not a prerequisite for the binding of RBP to prealbumin since it was shown that RBP from which the vitamin had been extracted retained its affinity for prealbumin. The data obtained in this study strongly suggest that the species devoid of both vitamin A and the COOH-terminal arginine is a catabolite of RBP.

Progesterone-binding Components of Chick Oviduct: I. PRELIMINARY CHARACTERIZATION OF CYTOPLASMIC COMPONENTS

Abstract Induction of the synthesis of the specific protein avidin by a single administration of progesterone has been demonstrated previously in chicks in vivo and in tissue minces and monolayer cultures of chick oviduct. To investigate the mechanism of induction, macromolecular components of oviduct cytoplasm which bind 3H-progesterone in vitro were isolated and characterized by sucrose gradient centrifugation, polyacrylamide gel electrophoresis, enzymatic digestion, and gel filtration on Agarose (Bio-Rad Laboratories, Richmond, California). The radioactive steroid in the isolated complex was identified as progesterone, not a metabolite, by paper chromatography. The interaction with 3H-progesterone has an apparent dissociation constant kd ≃ 8 x 10-10 m in 0.3 m KCl at 1° and is reversed by mild heating and by unlabeled progesterone g testosterone g 20α-hydroxy-4-pregnene-3-one g 17β-estradiol g cortisol g estrone g androstenedione. The participation of protein in the steroid-binding site was inferred from the destruction of the complex by 10-3 m p-hydroxymercuribenzoate and by Pronase, but not by ribo- or deoxyribonucleases. The apparent number and size of the cytoplasmic binding components vary with the concentration of KCl and the technique of isolation and detection. In the absence of KCl, the major components are characterized by sedimentation coefficients, s020,w, of about 5 S and 8 S, molecular weights of about 1.0 and 3.6 x 105 (estimated from the variation of electrophoretic mobility with gel concentration), and sufficiently large effective radii to be eluted in, or near, the void volume of columns of Agarose A-0.5m. Under the same conditions the corticosteroid-binding globulin (CBG) of chick plasma behaves as a single component with s020,w ≃ 3.7 S and mol wt ≃ 6.0 x 104. In solutions containing 0.3 m KCl, the cytoplasmic components and CBG all sediment at about the same rate but may be distinguished from each other by the distribution coefficients on Agarose A-0.5m. From the latter results, molecular Stokes radii of 55 and 63 A can be calculated for the cytoplasmic components, compared with 37 A for CBG. The progesterone-binding components of chick oviduct cytoplasm are thus distinguishable from CBG by all physicochemical methods tested. A functional role for these components in the induction of avidin synthesis by progesterone is supported by (a) the parallel order of effectiveness of various steroids in competing with progesterone binding and in potency as inducers, and (b) the analogous effects of treating the chicks with diethylstilbestrol on progesterone-binding activity and on avidin induction.

Physical studies of the interactions of acetylcholine chloride with membrane constituents.

The binding of acetylcholine to pure lipids, and lipids, proteins and lipoproteins extracted from synaptic membranes, was investigated by monolayer and n.m.r. techniques. No specific binding of acetylcholine could be detected at the concentration used, although its muscarinic and nicotinic antagonists [atropine and (+)-tubocurarine respectively] could be shown to interact with the membrane components. It is concluded that the binding of the nicotinic and muscarinic antagonists of acetylcholine is not necessarily indicative of the existence of a specific acetylcholine receptor. Measurements of the displacement of (45)Ca(2+) from monolayers of phosphatidylserine by acetylcholine and the variation of electrophoretic mobility of phosphatidylserine particles with concentration of acetylcholine indicated that in these systems acetylcholine was acting as a counterion at the negatively charged lipid interface. But studies of the salting-in and salting-out of negatively charged lipid aggregates showed that acetylcholine and other quaternary ammonium compounds did not here behave simply as counterions. Electrostrictively hydrated cations such as Na(+) and K(+) were found to salt out, whereas hydrophobically hydrated cations such as acetylcholine salted in such aggregates. The possible role of the hydration of acetylcholine in synaptic transmission is discussed.

Constant electrophoretic mobility of the cysteine-containing histone in plants and animals

The electrophoretic patterns of histones from diverse groups of living organisms have been compared. Two histone fractions show a total constancy of electrophoretic mobility no matter from what source they were isolated. The remaining three histone fractions (particularly the lysine-rich fraction) show distinct variations in electrophoretic mobility depending on the source of the histone. The implications of the data are discussed.

Une étude électrophorðique des complexes des lanthanides avec l'acide 1,2-diamino-cyclohexane-N,N,N′,N′-tétraacétique

The stability of the complexes of lanthanum and the lanthanides with 1,2-diamino-cyclohexane-N,N,N′,N′-tetraacetic acid was studied by means of paper electrophoresis. The variation in electrophoretic mobility was studied as a function of the pH and of the anionic concentration of the ligand. The conditions for maximum electrophoretic separation were determined. The instability constants were calculated by two methods and their dependence on the atomic number of the lanthanides was examined.

Effect of ribonuclease and neuraminidase on the electrophoretic mobility of tissue culture cells in parasynchronous growth.

AbstractCultured mammalian cells (RPMI no. 41) in parasynchronous growth were treated, at different stages of the mitotic cycle, with neuraminidase and ribonuclease, separately and sequentially, and their electrophoretic mobilities determined. Changes in the electrophoretic mobility of these cells are probably mainly due to variations in the density of negatively charged groups susceptible to neuraminidase, although variations in groups susceptible to ribonuclease may occur. It is suggested that the observed variations in electrophoretic mobility of different cells may be due to differences in the relative lengths of different life‐cycle phases. Where G2 phase is relatively long or G1 relatively short the cell populations will hve higher mean electrophoretic mobilities.

Strain variations of mouse Sγ1 globulins

Strain variations in the migration of the S γ1 globulin of mice have been demonstrated by immunoelectrophoresis. The variation of electrophoretic mobility seems to have a hereditary basis and was not accompanied by any detectable antigenic dissimilarity. The fast migration of the CBA 7 S γ1 was presumably not due to to the presence of sialic acid. Papain digestion of the 7 S γ1 from a strain of mice with 7 S γ1 of fast mobility (CBA) and a strain with slow mobility (C57BL/6) showed that both the F c and the F ab pieces migrated at rate similar to the parent molecule. In addition, the F c piece of the 7 S γ1 was seen to migrate faster than the F c piece of the 7 S γ2 globulin.

Electrophoretic Mobility of Milk Fat Globules. II. Effect of Diluent on Mobility of Fat Globules and Fat Globule Membrane

Microelectrophoretic mobility determinations on large numbers of individual milk fat globules suspended in distilled water demonstrated a wide variation in mobility between globules. The average mobility and variation in mobility decreased markedly when the suspending medium was a centrifugate prepared by means of superspeed centrifugation of milk. The variability is shown to be independent of milk fat globule size or age of the electrophoretic suspension. Mobility studies on washed cream showed an increase in mobility and an increased variation of mobility as the number of washings increased. Also, during washing of the cream, the distribution tended to broaden as the washing increased. Variation in electrophoretic mobility when either distilled water or centrifugate was used as the suspending media tended toward a normally distributed population. Mobility studies using the Tyndall phenomenon on fat globule membrane particles from buttermilk and butter serum fractions indicated these to be different.

Multiple haemoglobins in bats.

MULTIPLE haemoglobins and variation in electrophoretic mobility have been reported for many animals. The physiological significance of these discoveries is not completely understood. Some investigators have compared haemoglobin electrophoretic properties and phylogeny. Dunlap, Johnson and Farner1 analysed 21 species of birds and showed differences in haemoglobin apparently correlated with taxonomic kinship, and Marchlewska-Koj2 noted that amphibian haemoglobin heterogeneity may serve as complementary data for taxonomy. Comparable investigations of fish haemoglobins have been conducted by Hashimoto and Matsuura3,4, Smith5, and others, and of mammalian haemoglobins by Blumberg, Allison and Garry6, Foreman7, Ewy and Wojcik8, Buettner-Janusch9, Buettner-Janusch and Buettner-Janusch10 and others.