Variation In Protein Concentration Research Articles

Electrophoretic protein patterns in relation to low temperature tolerance and growth regulation of alfalfa

Disc electrophoresis and densitometry of polyacrylamide gel columns were used to evaluate the relationship between concentrations of water-soluble proteins of alfalfa and plant cold tolerance and growth. Variations in protein concentration were produced by hardening cultivars at different temperatures and by treating plants with chemicals. Cold-tolerant ‘Vernal’ and cold-sensitive ‘Arizona Common’ cultivars of alfalfa were given foliar applications of guanine, cytosine, gibberellic acid, 2-chloroethyltrimethyl ammonium chloride, or water and hardened at day temperatures of 7, 13, or 24 °C. After hardening for 40 days, cold-tolerance determinations and protein analyses were conducted on crown and root tissues. Protein concentrations of plant samples were found to vary most with plant cultivars, less with hardening temperature, and least with chemical treatments. Protein concentrations on 10 of 14 column regions and in total soluble protein were found to be closely associated with cold tolerance even though sizable alterations in growth were observed. It was concluded that either several proteins separated by electrophoresis or total soluble concentration per se may be intimately involved in the development of cold tolerance of alfalfa regardless of the amount of topgrowth produced during hardening.

The soluble proteins in eye lens nuclei of albacore, bluefin tuna and bonito

1. 1. Many samples of nuclear lens protein can now be electrophoretically processed at the same time, facilitating the identification of populations and the detection of rare protein variants. Multiple, simultaneous electrophoretic patterns of protein were prepared from lens nuclei of albacore, bluefin tuna and bonito. 2. 2. No variation was found among the albacore patterns. However, while acidic protein polymorphism, which is common, was revealed in the bluefin patterns, the bonito patterns revealed a rare polymorphism—a variably present, highly basic protein. Variation in protein concentration is apparently controlled by multiple genes.

In vivo observation on cyclic variations of estradiol-17beta,6,7-3H uptake by the uterus of the adult rat.

Estradiol-17β,6.7-3H uptake in rat uterus and endometrium was studied at the end of 4-hr intravenous infusions at different phases of the estrous cycle. Different rates of infusion were used. A definite cyclic variation in estradiol-17β,6,7-3H concentration in uterus and endometrium was observed, being lowest at estrus and highest at diestrus, at all infusion rates (from 4.9 to 703 ng/hr). Cyclic changes were parallel in uterus and endometrium. Cyclic variation of estradiol-17β concentration in uterus and endometrium did not parallel the cyclic variation of protein concentration in these tissues. The maximal concentration in uterus, i.e., the “tissue capacity” (NmSu), was found to be: 2.3 ±0.3, 1.8 ±0.2, 2.7 ±0.13 and 2.7 ±0.2 (SD) × l0-8 moles/kg at proestrus, estrus, metestrus and diestrus, respectively. The plasma concentration at half saturation of the uterus (i.e., the “biological exchange constant” (1/Kpu)) was 3.7 ±0.7, 4.5 ±0.6, 3.5 ±0.2 and 3.3 ±0.3 (SD) × 10-10M at these respective phases. Lower...

Volume change associated with the G-F transformation of flagellin

The volume change of the solution, Δ V, associated with the polymerization at neutral pH of the protein, flagellin, to flagella, a typical G-F transformation, was measured with a Carlsberg-type dilatometer. A large positive volume change, greater than 150 ml. per mole of flagellin polymerized, was observed for this process. The effect of variations in protein concentration and temperature on Δ V was studied. Both the final value of Δ V observed after complete polymerization of flagellin had occurred, Δ V max, as well as the rate of the volume change on polymerizing flagellin, estimated as the reciprocal of the mid-plateau value ( tΔ V max 2) −1 , were found to be temperature-dependent. Between 22 and 28 °C the polymerization, rate increased with increasing temperature. However, over this temperature range ΔV max was unchanged and had a value of 157 ± 4 ml. per mole of flagellin polymerized. Above 28 °C the polymerization rate decreased with increasing temperature but ΔV max increased to a maximum value at 35 °C of 306 ml. per mole of flagellin polymerized. At temperatures higher than 35 °C, the rate for the volume change decreases markedly and polymerization, as measured by changes in specific viscosity, does not occur. The effect of increasing temperature on the rate and magnitude of the volume changes observed is explained by assuming that the protein can be reversibly transformed to a state which lacks the capacity to reconstitute flagella, and that at temperatures above 28 °C this transformation becomes rate limiting for the polymerization process. Such a reversible transformation of flagellin can explain some of the well-known effects of temperature on the expression of motility and the formation of flagella in vivo.

Denaturation studies on prostatic acid phosphatase

The heat denaturation of prostatic acid phosphatase has been studied in a controlled system, as a function of a number of primary environmental variables. The factors of ionic strength and variations in protein concentration were shown to be negligible or controllable. The nature of anion in the buffer system profoundly affects the denaturation rate. The multivalent anions accelerate the rate rapidly for increasing low molarities, whereas the rates decrease after passing through a maximum for higher concentrations. Ions of lower valency give rates increasing with concentration, with no maxima. The activation energy is constant regardless of buffer or pH used.

EXOPHTHALMIC GOITER

One of us (W.O.T.) has previously shown that the concentration of protein in cerebrospinal fluid is high in most cases of myxedema, and usually drops to within normal limits following the administration of desiccated thyroid. 1 Similar measurements 2 have now been made in several cases of exophthalmic goiter before any treatment was started and after the body weight had reached a stationary level following a subtotal thyroidectomy. The observations are the opposite of those in myxedema. Before treatment, the concentration of protein is usually within the lower limits of normal. 3 It shows a well marked increase (eleven out of fifteen cases) in association with a gain in body weight and a reduction in basal metabolism after operation. This is illustrated in fifteen unselected cases in the accompanying table and illustration. It may be noted that, as usual, there are wide individual variations in protein concentration. Our experience has been, however, that